Note: Explore this map with the activity The Underground Railroad.This map shows which states and territories in 1850 permitted the enslavement of people, and which did not. Slavery had been practiced in North America since well before the United States was founded in 1776, and by 1850 it was a key part of the agricultural economy of the southern states. Large cotton plantations operated on the labor of enslaved people, particularly Black Africans. Meanwhile, the northern United States had a more industrial economy, and by 1850 had mostly prohibited slavery for economic, political, and moral reasons. Though these states were considered “free” states, in many cases this meant that slavery wasn’t widespread. Even in states and territories where slavery was technically illegal, there were many loopholes that kept people enslaved and restricted free Black people.
In the years before the American Civil War, which began in 1861, the question of whether new states would allow slavery caused a lot of disagreement and tension between the North and South. The United States was carefully balanced to have as many "slave" states as "free" states, giving both sides an equal number of senators. The South was worried that if more free states were added, this balance would be upset, and the North would be able to pass legislation banning slavery in the United States. The North didn't want slavery to spread to new areas, both for moral reasons and because they didn’t think it was fair that enslaved people couldn’t vote but counted as part of the population when assigning congressional delegates. They argued that this gave the South an unfair advantage when voting for new laws. To try to keep the peace, a series of compromises, such as the Missouri Compromise of 1820 were proposed to determine what states and territories would or would not permit slavery.
Another issue that caused tension between abolitionists in the North and slave owners in the South was the ongoing trade of enslaved people. The United States government had banned foreign slave trade in 1800, but this did nothing to free the people who were already enslaved in the United States. States in the upper South, such as Virginia, now profited from selling enslaved people to new states in the Deep South.
To escape enslavement, some enslaved people used an informal network of routes, places, and people known as the Underground Railroad to travel in secret to the Northern United States and into Canada, where slavery was illegal. The Underground Railroad was not a literal underground railroad, but because escaping from slavery and helping enslaved people escape was illegal, the network operated in secret. The “conductors” were the people leading enslaved people to freedom and the “station masters,” those who hid enslaved people on the way north. According to some estimates, between 1810 and 1850, the Underground Railroad helped to guide 100,000 enslaved people to freedom.
This map was made through the process of digitization, or tracing historical maps using modern geographic information system (GIS) software. These maps don’t always line up perfectly with modern boundaries, for many reasons. Over time, natural landmarks, such as rivers, can shift their paths, and human landmarks, such as buildings and roads, can be abandoned and demolished. There are also differences in the accuracy of hand-drawn maps compared to computer-drawn maps.
The original maps are published in Harper’s Atlas of American History, and are available through the Library of Congress:
Slavery and Slave Trade 1830-1850
Routes of the Underground Railroad 1830-1865
Fox, Dixon Ryan. Harper's atlas of American history, selected from "The American nation series," with map studies, by Dixon Ryan Fox. [New York, London, Harper & Brothers, 1920] Pdf. https://www.loc.gov/item/32005827/
FIRE1850_POLY: One of a series of four maps showing the state of forests in the northern coastal area of Oregon. They show the change in stand age over time due to fires. This dataset shows conditions in 1850.
Colour raster copies of maps by Czech and European cartographers, cartographic shops and publishing houses up to year 1850. Maps and plans and usually printed, exceptionally manuscripts. The collection is divided into three parts: Czech maps, foreign territory, city plans.
Historical shoreline change is considered to be a crucial element in studying the vulnerability of the national shoreline. These data are used in a shoreline change analysis for the USGS National Assessment Project. There are critical needs for a nationwide compilation of reliable shoreline data. To meet these needs, the USGS has produced a comprehensive database of digital vector shorelines by compiling shoreline positions from pre-existing historical shoreline databases and by generating historical and modern shoreline data. Shorelines are compiled by state and generally correspond to one of four time periods: 1800s, 1920s-1930s, 1970s, and 1998-2002. Each shoreline may represent a compilation of data from one or more sources for one or more dates provided by one or more agencies. Details regarding source are provided in the 'Data Quality Information' section of this metadata report. Shoreline vectors derived from historic sources (first three time periods) represent the high water line at the time of the survey, whereas modern shorelines (final time period) represent the mean high water line. .
Colour raster copies of maps by Czech and European cartographers, cartographic shops and publishing houses up to year 1850. Maps and plans and usually printed, exceptionally manuscripts. The collection is divided into three parts: Czech maps, foreign territory, city plans.
Attribution-NonCommercial-ShareAlike 4.0 (CC BY-NC-SA 4.0)https://creativecommons.org/licenses/by-nc-sa/4.0/
License information was derived automatically
Author: A Kloempken, educator, Minnesota Alliance for Geographic EducationGrade/Audience: grade 6, grade 7Resource type: lessonSubject topic(s): maps, historyRegion: united statesStandards: Standard 1. People use geographic representations and geospatial technologies to acquire, process and report information within a spatial context.
Standard 2. Historical inquiry is a process in which multiple sources and different kids of historical evidence are analyzed to draw conclusions about what happened in the past, and how and why it happened.
Standard 19. Regional tensions around economic development, slavery, territorial expansion and governance resulted in a civil war and a period of Reconstruction that led to the abolition of slavery, a more powerful federal governments, a renewed push into indigenous nations' territory and continuing conflict over racial relations (Civil War and Reconstruction 1850-1877) Objectives: Students will be able to:
Although the founding fathers declared American independence in 1776, and the subsequent Revolutionary War ended in 1783, individual states did not officially join the union until 1787. The first states to ratify the U.S. Constitution were Delaware, Pennsylvania and New Jersey, in December 1787, and they were joined by the remainder of the thirteen ex-British colonies by 1790. Another three states joined before the turn of the nineteenth century, and there were 45 states by 1900. The final states, Alaska and Hawaii, were admitted to the union in 1959, almost 172 years after the first colonies became federal states. Secession in the American Civil War The issues of slavery and territorial expansion in the mid nineteenth century eventually led to the American Civil War, which lasted from 1861 until 1865. As the U.S. expanded westwards, a moral and economic argument developed about the legality of slavery in these new states; northern states were generally opposed to the expansion of slavery, whereas the southern states (who were economically dependent on slavery) saw this lack of extension as a stepping stone towards nationwide abolition. In 1861, eleven southern states seceded from the Union, and formed the Confederate States of America. When President Lincoln refused to relinquish federal property in the south, the Confederacy attacked, setting in motion the American Civil War. After four years, the Union emerged victorious, and the Confederate States of America was disbanded, and each individual state was readmitted to Congress gradually, between 1866 and 1870. Expansion of other territories Along with the fifty U.S. states, there is one federal district (Washington D.C., the capital city), and fourteen overseas territories, five of which with a resident population (American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S. Virgin Islands). In 2019, President Trump inquired about the U.S. purchasing the territory of Greenland from Denmark, and, although Denmark's response indicated that this would be unlikely, this does suggest that the US may be open to further expansion of it's states and territories in the future. There is also a movement to make Washington D.C. the 51st state to be admitted to the union, as citizens of the nation's capital (over 700,000 people) do not have voting representation in the houses of Congress nor control over many local affairs; as of 2020, the U.S. public appears to be divided on the issue, and politicians are split along party lines, as D.C. votes overwhelmingly for the Democratic nominee in presidential elections.
Contained within the 3rd Edition (1957) of the Atlas of Canada is a plate that shows the distribution of population in what is now Canada circa 1851, 1871, 1901, 1921 and 1941. The five maps display the boundaries of the various colonies, provinces and territories for each date. Also shown on these five maps are the locations of principal cities and settlements. These places are shown on all of the maps for reference purposes even though they may not have been in existence in the earlier years. Each map is accompanied by a pie chart providing the percentage distribution of Canadian population by province and territory corresponding to the date the map is based on. It should be noted that the pie chart entitled Percentage Distribution of Total Population, 1851, refers to the whole of what was then British North America. The name Canada in this chart refers to the province of Canada which entered confederation in 1867 as Ontario and Quebec. The other pie charts, however, show only percentage distribution of population in what was Canada at the date indicated. Three additional graphs are included on this plate and show changes in the distribution of the population of Canada from 1867 to 1951, changes in the percentage distribution of the population of Canada by provinces and territories from 1867 to 1951 and elements in the growth of the population of Canada for each ten-year period from 1891 to 1951.
The California State Lands Commission (CSLC) was created by the California Legislature in 1938 and given the authority and responsibility to manage certain public lands within the state. The public lands under the Commission’s jurisdiction are of two distinct types—sovereign lands acquired upon California’s admission into the Union in 1850; and certain federally granted lands including school lands, and swamp and overflowed lands. For purposes of this GIS data, sovereign lands are considered to be further divided into two general categories—fixed-boundary sovereign lands and ambulatory-boundary sovereign lands. The following lands are included in this data: Portions of the ambulatory-boundary for state sovereign lands at a specific point in time, for portions of the San Joaquin River. NOT INCLUDED IN THIS DATA: School lands: These are what remains of nearly 5.5 million acres throughout the state originally granted to California by Congress in 1853 to benefit public education. Fixed-boundary sovereign lands: These are sovereign, public trust lands having fixed boundaries as the result of land exchanges, boundary line agreements or court orders. Swamps and overflowed lands: These are what remain of federal lands granted to California by Congress in 1850 to encourage reclamation and development of agricultural lands. ALSO NOT INCLUDED IN THIS DATA: Ownership details within the U.S. Government meanders of Owens Lake. THIS DATA SUPERSEDES all previously published GIS information with respect to the above described state-owned lands under the jurisdiction of the CSLC.
Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
License information was derived automatically
This data was created to depict portions of state-owned Sovereign Lands that are under the jurisdiction of the California State Lands Commission. Data coverage is currently limited to reaches 1A, 4A and 4B1 of the San Joaquin River.
The California State Lands Commission (CSLC) was created by the California Legislature in 1938 and given the authority and responsibility to manage certain public lands within the state. The public lands under the Commission’s jurisdiction are of two distinct types—sovereign lands acquired upon California’s admission into the Union in 1850; and certain federally granted lands including school lands, and swamp and overflowed lands. For purposes of this GIS data, sovereign lands are considered to be further divided into two general categories—fixed-boundary sovereign lands and ambulatory-boundary sovereign lands.
The following lands are included in this data:
· Portions of the ambulatory-boundary for state sovereign lands at a specific point in time, for portions of the San Joaquin River.
NOT INCLUDED IN THIS DATA:
· School lands: These are what remains of nearly 5.5 million acres throughout the state originally granted to California by Congress in 1853 to benefit public education.
· Fixed-boundary sovereign lands: These are sovereign, public trust lands having fixed boundaries as the result of land exchanges, boundary line agreements or court orders.
· Swamps and overflowed lands: These are what remain of federal lands granted to California by Congress in 1850 to encourage reclamation and development of agricultural lands.
ALSO NOT INCLUDED IN THIS DATA: Ownership details within the U.S. Government meanders of Owens Lake.
THIS DATA SUPERSEDES all previously published GIS information with respect to the above described state-owned lands under the jurisdiction of the CSLC.
Colour raster copies of maps by Czech and European cartographers, cartographic shops and publishing houses up to year 1850. Maps and plans and usually printed, exceptionally manuscripts. The collection is divided into three parts: Czech maps, foreign territory, city plans.
The SPATIAL LOCATION of railroads/ is based upon locations as given in the National Transportation Atlas Database (United States Department of Transportation, Bureau of Transportation Statistics) and contemporary and historical U.S. topographical maps (United States Department of the Interior, U.S. Geological Survey)./The EXISTENCE of a railroad serving locations at a specific date (see variable "InOpBy") was determined using the following resources: 1911: state maps from William D. Whitney and Benjamin E. Smith (eds) The Century dictionary and cyclopedia, with a new atlas of the world, New York: Century Co., 1911 (using scanned images from http://www.goldbug.com); 1903: regional maps from Rand McNally, Rand McNally & Co.'s Enlarged Business Atlas And Shippers' Guide ... Showing In Detail The Entire Railroad System ... Accompanied By A New And Original Compilation And Ready Reference Index…, Chicago: Rand McNally & Company, 1903 (using images 2844006, 2844007 and 2844008 from http://www.davidrumey.com); 1898: regional maps from Rand McNally, United States. Rand, McNally & Co., Map Publishers and Engravers, Chicago, 1898. Rand, McNally & Co.'s New Business Atlas Map of the United States…, Chicago: Rand McNally & Company, 1898 (using images 0772003, 0772004 and 0772005 from http://www.davidrumey.com); 1893: state maps from Rand McNally and Company, Rand, McNally & Co.'s enlarged business atlas and shippers guide ; containing large-scale maps of all the states and territories in the United States, of the Dominion of Canada, the Republic of Mexico, Central America, the West Indies and Cuba. Chicago: Rand McNally, 1893 (images courtesy of Murray Hudson, www.antiquemapsandglobes.com) except for Louisiana, Maryland/Delaware, Michigan, and Mississippi which were taken from Rand McNally, Universal Atlas of the World, Chicago: Rand McNally, 1893 (images courtesy of the University of Alabama Cartographic Lab) and Texas which was digitized by Amanda Gregg from Rand McNally & Co. Indexed county and railroad pocket map and shippers' guide of Texas : accompanied by a new and original compilation and ready reference index, showing in detail the entire railroad system ...Chicago: Rand McNally & Co., c1893 (Yale University Beinecke Library, Call Number: Zc52 893ra); 1889: state maps from Rand McNally, Rand, McNally & Co.'s enlarged business atlas and shippers guide…, Chicago: Rand McNally & Co., 1889 (using images 2094016 through 2094062 from http://www.davidrumey.com); 1881: state maps from Rand McNally, New Indexed Business Atlas and Shippers Guide, Chicago: Rand McNally & Co., 1881 (photographed by Amanda Gregg from a copy in the Yale University Beinecke Library, 2009 Folio 63); 1877: state maps from Rand McNally and Company, Rand McNally & Co’s Business Atlas, Chicago: Rand McNally & Co., 1877 (digitized by Matthew Van den Berg from a copy in the Library of Congress, Call no. G1200 .R3358 1877); 1872: regional maps from Warner & Beers, Atlas of the United States, Chicago: Warner & Beers, 1872 (using images 2585069 through 2585078 from http://www.davidrumey.com);1868: national map by J. T. Lloyd, Lloyd's New Map of the United States The Canadas and New Brunswick From The Latest Surveys Showing Every Railroad & Station Finished … 1868, New York: J. T. Lloyd, 1868 (using image 2859002 from http://www.davidrumey.com)1863: national map by J. T. Lloyd, Lloyd's New Map of the United States The Canadas And New Brunswick From the latest Surveys Showing Every Railroad & Station Finished to June 1863, New York: J. T. Lloyd, 1863 (using image 2591002 from http://www.davidrumey.com)1861: regional maps by G. R. Taylor and Irene D. Neu, The American Railroad Network 1861-1890, Cambridge, Mass: Harvard University Press, 1956;1858: national map by Hugo Stammann, J. Sage & Son's new & reliable rail road map comprising all the railroads of the United States and Canadas with their stations and distances, Buffalo, NY: J Sage & Sons, 1858 using image rr000360 from the Library of Congress at http://hdl.loc.gov/loc.gmd/g3701p.rr000360;1856: national map by Richard S. Fisher, Dinsmore's complete map of the railroads & canals in the United States & Canada carefully compiled from authentic sources by Richard S. Fisher, editor of the American Rail Road & Steam Navigation Guide, New York, 1856 using image rr000300 from the Library of Congress at http://hdl.loc.gov/loc.gmd/g3701p.rr000300;1854: national map by E. D. Sanford, H. V. Poor's rail road map showing particularly the location and connections of the North East & South West Alabama Rail Road, by E. D. Sanford, Civil Engineer, n.p.: 1854 using image rr004950 from the Library of Congress at http://hdl.loc.gov/loc.gmd/g3701p.rr004950;1852: national map by J. H. Colton, Colton's Map Of The United States, The Canadas &c. Showing The Rail Roads, Canals & Stage Roads: With Distances from Place to Place, New York: J. H. Colton, 1852 (using image 0172002 from http://www.davidrumey.com)1850 and earlier dates: Curran Dinsmore, Dinsmore & Company's new and complete map of the railway system of the United States and Canada; compiled from official sources, under the direction of the editor of the "American Railway Guide.", New York: 1850, the early railroad database assembled by Professor Milton C. Hallberg (deceased, Pensylvania State University) and appearing on http://oldrailhistory.com/, various railroad histories, on-line google search results and Wikipedia entries for specific railroads appearing in Hallberg’s database. Digitized maps were geo-referenced using ArcGIS 10’s spline algorithm against the National Historical Geographic Information System’s 2009 TIGER-based historical state and county boundary files (see www.nhgis.org) and the U.S. National Atlas’s database of cities and town.No effort was made to identify or preserve double tracking. Sidings, yards, and turnouts, etc., were deleted whenever possible absent any knowledge as to when these features were constructed.See Jeremy Atack "Procedures and Issues Relating to the Creration of Historical Transportation Shapfiles of Navigabale Rivers, Canals, and Railroads in the United States" available at https://my.vanderbilt.edu/jeremyatack/files/2015/09/HistoricalTransportationSHPfilesDocumenation.pdf. Also Jeremy Atack, "On the Use of Geographic Informations Systems in Economic History" Journal of Economic History, 73:2 (June 2013): 313-338. Also available at https://my.vanderbilt.edu/jeremyatack/files/2011/08/EHAPresidentialAddress.pdfRevision History: Edited = 1 ==> minor modifications by Jeremy Atack, September 20, 2015 amending dates for "InOpBy" and/or endpoints to fix microfractures and inconsistencies,1861 or earlier.= 2 ==> JA; 9/21/2015 switched dates and names (1861-1903) on Charleston & Savannah RR just west of Ashley River to accurately reflect LOC map for this RR= 3 ==> JA: 12/22/2015 modification to RR dates and locations around Baltimore, New York city, Philadelphia and Washington DC reflecting (some but not all) of the 1860 mapping by C. Baer et al., Canals and Railroads of the Mid-Atlantic States, 1800-1860 (Hagley Foundation 1981)SHP file edited 5/9/2016 to fix error message in ArcCatalog caused by 4 "phantom" features (InOpBy=blank/zero) that had no geometry associated with them.
There are critical needs for a nationwide compilation of reliable shoreline data. To meet these needs, the USGS has produced a comprehensive database of digital vector shorelines by compiling shoreline positions from pre-existing historical shoreline databases and by generating historical and modern shoreline data. Shorelines are compiled by state and generally correspond to one of four time periods: 1800s, 1920s-1930s, 1970s, and 1998-2002. Each shoreline may represent a compilation of data from one or more sources for one or more dates provided by one or more agencies. Details regarding source are provided in the 'Data Quality Information' section of this metadata report. Shoreline vectors derived from historic sources (first three time periods) represent the high water line at the time of the survey, whereas modern shorelines (final time period) represent the mean high water line.
Barevné rastrové kopie map českých i evropských kartografů, kartografických dílen a vydavatelství do roku 1850. Zpravidla jde o mapy a plány tištěné, výjimečně i rukopisné. Soubor je rozdělen do tří celků: bohemika, zahraniční území, plány měst.
Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
License information was derived automatically
🇺🇸 미국 English This data was created to depict portions of state-owned Sovereign Lands that are under the jurisdiction of the California State Lands Commission. Data coverage is currently limited to reaches 1A, 4A and 4B1 of the San Joaquin River.The California State Lands Commission (CSLC) was created by the California Legislature in 1938 and given the authority and responsibility to manage certain public lands within the state. The public lands under the Commission’s jurisdiction are of two distinct types—sovereign lands acquired upon California’s admission into the Union in 1850; and certain federally granted lands including school lands, and swamp and overflowed lands. For purposes of this GIS data, sovereign lands are considered to be further divided into two general categories—fixed-boundary sovereign lands and ambulatory-boundary sovereign lands. The following lands are included in this data: · Portions of the ambulatory-boundary for state sovereign lands at a specific point in time, for portions of the San Joaquin River. NOT INCLUDED IN THIS DATA: · School lands: These are what remains of nearly 5.5 million acres throughout the state originally granted to California by Congress in 1853 to benefit public education. · Fixed-boundary sovereign lands: These are sovereign, public trust lands having fixed boundaries as the result of land exchanges, boundary line agreements or court orders. · Swamps and overflowed lands: These are what remain of federal lands granted to California by Congress in 1850 to encourage reclamation and development of agricultural lands. ALSO NOT INCLUDED IN THIS DATA: Ownership details within the U.S. Government meanders of Owens Lake. THIS DATA SUPERSEDES all previously published GIS information with respect to the above described state-owned lands under the jurisdiction of the CSLC.
Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
License information was derived automatically
This dataset presents spatiotemporal dynamics of phosphorus (P) fertilizer management (application rate, timing, and method) at a 4km × 4 km resolution in agricultural land of the contiguous U.S. from 1850 to 2022. By harmonizing multiple data sources, we reconstructed the county-level crop-specific P fertilizer use history. We then spatialized and resampled P fertilizer use data to 4 km × 4 km gridded maps based on historical U.S. cropland distribution and crop type database developed by Ye et al. (2024).
This dataset contains (1) P fertilizer total consumption and mean application rate at the national level (Tabular); (2) P fertilizer consumption of 11 crops at the state level (Tabular); (3) P fertilizer consumption of permanent pasture (Tabular); (4) P fertilizer consumption of non-farm at the state level (Tabular); (5) P fertilizer application rate of 11 crop types at the state level (Tabular); (6) P fertilizer application rate of 11 crop types at the county level (Tabular); (7) P fertilizer application timing ratio at the state level (Tabular); (8) P fertilizer application method ratio at the state level (Tabular); (9) Gridded maps of P fertilizer application rate based on state-level data; (10) and (11) Gridded maps of P fertilizer application rate based on county-level data; (12)-(20) Gridded maps of P fertilizer application rate for each crop.
A detailed description of the data development processes, key findings, and uncertainties can be found in Cao, P., Yi, B., Bilotto, F., Gonzalez Fischer, C., Herrero, M., Lu, C.: Crop-specific Management History of Phosphorus fertilizer input (CMH-P) in the croplands of United States: Reconciliation of top-down and bottom-up data sources, is under review for the journal Earth System Science Data (ESSD). https://essd.copernicus.org/preprints/essd-2024-67/#discussion.
This work is supported by the Iowa Nutrient Research Center, the ISU College of Liberal Arts and Sciences Dean's Faculty Fellowship, and NSF CAREER grant (1945036).
There are critical needs for a nationwide compilation of reliable shoreline data. To meet these needs, the USGS has produced a comprehensive database of digital vector shorelines by compiling shoreline positions from pre-existing historical shoreline databases and by generating historical and modern shoreline data. Shorelines are compiled by state and generally correspond to one of four time periods: 1800s, 1920s-1930s, 1970s, and 1998-2002. Each shoreline may represent a compilation of data from one or more sources for one or more dates provided by one or more agencies. Details regarding source are provided in the 'Data Quality Information' section of this metadata report. Shoreline vectors derived from historic sources (first three time periods) represent the high water line at the time of the survey, whereas modern shorelines (final time period) represent the mean high water line.
Barevné rastrové kopie map českých i evropských kartografů, kartografických dílen a vydavatelství do roku 1850. Zpravidla jde o mapy a plány tištěné, výjimečně i rukopisné. Soubor je rozdělen do tří celků: bohemika, zahraniční území, plány měst.
Link to the ScienceBase Item Summary page for the item described by this metadata record. Service Protocol: Link to the ScienceBase Item Summary page for the item described by this metadata record. Application Profile: Web Browser. Link Function: information
Link to the ScienceBase Item Summary page for the item described by this metadata record. Service Protocol: Link to the ScienceBase Item Summary page for the item described by this metadata record. Application Profile: Web Browser. Link Function: information
Note: Explore this map with the activity The Underground Railroad.This map shows which states and territories in 1850 permitted the enslavement of people, and which did not. Slavery had been practiced in North America since well before the United States was founded in 1776, and by 1850 it was a key part of the agricultural economy of the southern states. Large cotton plantations operated on the labor of enslaved people, particularly Black Africans. Meanwhile, the northern United States had a more industrial economy, and by 1850 had mostly prohibited slavery for economic, political, and moral reasons. Though these states were considered “free” states, in many cases this meant that slavery wasn’t widespread. Even in states and territories where slavery was technically illegal, there were many loopholes that kept people enslaved and restricted free Black people.
In the years before the American Civil War, which began in 1861, the question of whether new states would allow slavery caused a lot of disagreement and tension between the North and South. The United States was carefully balanced to have as many "slave" states as "free" states, giving both sides an equal number of senators. The South was worried that if more free states were added, this balance would be upset, and the North would be able to pass legislation banning slavery in the United States. The North didn't want slavery to spread to new areas, both for moral reasons and because they didn’t think it was fair that enslaved people couldn’t vote but counted as part of the population when assigning congressional delegates. They argued that this gave the South an unfair advantage when voting for new laws. To try to keep the peace, a series of compromises, such as the Missouri Compromise of 1820 were proposed to determine what states and territories would or would not permit slavery.
Another issue that caused tension between abolitionists in the North and slave owners in the South was the ongoing trade of enslaved people. The United States government had banned foreign slave trade in 1800, but this did nothing to free the people who were already enslaved in the United States. States in the upper South, such as Virginia, now profited from selling enslaved people to new states in the Deep South.
To escape enslavement, some enslaved people used an informal network of routes, places, and people known as the Underground Railroad to travel in secret to the Northern United States and into Canada, where slavery was illegal. The Underground Railroad was not a literal underground railroad, but because escaping from slavery and helping enslaved people escape was illegal, the network operated in secret. The “conductors” were the people leading enslaved people to freedom and the “station masters,” those who hid enslaved people on the way north. According to some estimates, between 1810 and 1850, the Underground Railroad helped to guide 100,000 enslaved people to freedom.
This map was made through the process of digitization, or tracing historical maps using modern geographic information system (GIS) software. These maps don’t always line up perfectly with modern boundaries, for many reasons. Over time, natural landmarks, such as rivers, can shift their paths, and human landmarks, such as buildings and roads, can be abandoned and demolished. There are also differences in the accuracy of hand-drawn maps compared to computer-drawn maps.
The original maps are published in Harper’s Atlas of American History, and are available through the Library of Congress:
Slavery and Slave Trade 1830-1850
Routes of the Underground Railroad 1830-1865
Fox, Dixon Ryan. Harper's atlas of American history, selected from "The American nation series," with map studies, by Dixon Ryan Fox. [New York, London, Harper & Brothers, 1920] Pdf. https://www.loc.gov/item/32005827/