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/

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.

In the past four centuries, the population of the United States has grown from a recorded 350 people around the Jamestown colony of Virginia in 1610, to an estimated 331 million people in 2020. The pre-colonization populations of the indigenous peoples of the Americas have proven difficult for historians to estimate, as their numbers decreased rapidly following the introduction of European diseases (namely smallpox, plague and influenza). Native Americans were also omitted from most censuses conducted before the twentieth century, therefore the actual population of what we now know as the United States would have been much higher than the official census data from before 1800, but it is unclear by how much. Population growth in the colonies throughout the eighteenth century has primarily been attributed to migration from the British Isles and the Transatlantic slave trade; however it is also difficult to assert the ethnic-makeup of the population in these years as accurate migration records were not kept until after the 1820s, at which point the importation of slaves had also been illegalized. Nineteenth century In the year 1800, it is estimated that the population across the present-day United States was around six million people, with the population in the 16 admitted states numbering at 5.3 million. Migration to the United States began to happen on a large scale in the mid-nineteenth century, with the first major waves coming from Ireland, Britain and Germany. In some aspects, this wave of mass migration balanced out the demographic impacts of the American Civil War, which was the deadliest war in U.S. history with approximately 620 thousand fatalities between 1861 and 1865. The civil war also resulted in the emancipation of around four million slaves across the south; many of whose ancestors would take part in the Great Northern Migration in the early 1900s, which saw around six million black Americans migrate away from the south in one of the largest demographic shifts in U.S. history. By the end of the nineteenth century, improvements in transport technology and increasing economic opportunities saw migration to the United States increase further, particularly from southern and Eastern Europe, and in the first decade of the 1900s the number of migrants to the U.S. exceeded one million people in some years. Twentieth and twenty-first century The U.S. population has grown steadily throughout the past 120 years, reaching one hundred million in the 1910s, two hundred million in the 1960s, and three hundred million in 2007. In the past century, the U.S. established itself as a global superpower, with the world's largest economy (by nominal GDP) and most powerful military. Involvement in foreign wars has resulted in over 620,000 further U.S. fatalities since the Civil War, and migration fell drastically during the World Wars and Great Depression; however the population continuously grew in these years as the total fertility rate remained above two births per woman, and life expectancy increased (except during the Spanish Flu pandemic of 1918).

Since the Second World War, Latin America has replaced Europe as the most common point of origin for migrants, with Hispanic populations growing rapidly across the south and border states. Because of this, the proportion of non-Hispanic whites, which has been the most dominant ethnicity in the U.S. since records began, has dropped more rapidly in recent decades. Ethnic minorities also have a much higher birth rate than non-Hispanic whites, further contributing to this decline, and the share of non-Hispanic whites is expected to fall below fifty percent of the U.S. population by the mid-2000s. In 2020, the United States has the third-largest population in the world (after China and India), and the population is expected to reach four hundred million in the 2050s.