Maps
US History maps
Step through the borders as they really were on key dates, and see what changed and why it matters. Every border comes from an open historical dataset, and each map says where its shapes come from and what they leave out.
The thirteen colonies in 1775
The British colonies on the eve of the Revolution, grouped into the regions you need to compare.
19 April 1775, the day of Lexington and Concord · Units 2, 3
How the United States grew, 1783–1898
Every big addition of land, from the Treaty of Paris to Hawaii, one step at a time.
9 steps: 1783, 1803, 1819, 1845, 1846, 1848, 1853, 1867, 1898 · Units 3, 4, 5, 6, 7
Free and slave states, 1821–1861
The Missouri Compromise, the Compromise of 1850, the Kansas–Nebraska Act and secession, on the borders of the day.
4 steps: 1820, 1850, 1854, 1861 · Units 4, 5
When each state joined the Union
All 50 states, shaded by when they joined, from the first 13 to Alaska and Hawaii.
Borders as of 2000 · Units 3, 4, 5, 6
American empire overseas, 1898–1917
The islands the United States took or bought across the Pacific and the Caribbean.
3 steps: 1898, 1900, 1917 · Units 7