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/

Abstract (en): This data collection contains complete roll call records for the approximately 1,900 votes taken in both chambers of the three Confederate Congresses in the period 1862-1865. Included also is a biographical file that provides data on all those who were seated in any of the Confederate Congresses, including each member's name, age, state, district, party identification, and vocation, as well as the extent of the Congressman's landholdings, the number of slaves held, whether or not the district was occupied by union troops, and the member's stand on secession. ICPSR data undergo a confidentiality review and are altered when necessary to limit the risk of disclosure. ICPSR also routinely creates ready-to-go data files along with setups in the major statistical software formats as well as standard codebooks to accompany the data. In addition to these procedures, ICPSR performed the following processing steps for this data collection: Performed consistency checks.. All voting members of both chambers of the three Confederate Congresses in the United States in the period 1862-1865. The data map is provided as an ASCII text file.

The election of Abraham Lincoln in November of 1860 brought to a head the issue of slavery in the United States. In direct response to Lincoln's election as president, seven southern states seceded from the Union rather than continue to negotiate and compromise over the issue of slavery, which had been the norm for so many decades.This story map locates most of the major battles of the American Civil War. It was developed in partnership with the American Battlefield Trust.Many of the descriptions for individual sites include links to excellent battlefield maps, articles and in-depth analysis from the American Battlefield Trust. The Trust is America's largest non-profit organization devoted to the preservation of our nation's endangered battlefields. The Trust also promotes educational programs and heritage tourism initiatives to inform the public of the war's history and the fundamental conflicts that sparked it. See additional story maps at esri.com/arcgisstorymaps.

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:

1. Understand the parts of a map (TODALSS)
2. Read and analyze a map.
3. Compare maps as primary and secondary sources.
4. Develop guiding questions for research.Summary: This lesson will aid students throughout the grade levels to understand historic maps and how to analyze them. Here, maps of the Battle of Gettysburg are used for research into Minnesota' role in the battle.

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.