How the United States grew, 1783–1898
Every big addition of land, from the Treaty of Paris to Hawaii, one step at a time.
Orange is the land added in the step you're looking at. Blue is land the United States already had.
Every step in words
1783: The Treaty of Paris
Borders as of 3 September 1783
Britain recognized American independence and drew the new country's borders: the Great Lakes in the north, the Mississippi River in the west and Spanish Florida in the south.
The new country reached far past where most Americans lived. Who would control the land between the Appalachians and the Mississippi, and what that meant for the Native nations living there, became one of the new government's first big questions. The Northwest Ordinance of 1787 set out how that land would become new states, and banned slavery north of the Ohio River.
1803: The Louisiana Purchase
Borders as of 30 April 1803
Jefferson bought Louisiana from France for $15 million, roughly doubling the size of the country. Its western border wasn't clearly set; the shape here is the land drained by the Mississippi's western rivers.
The purchase gave Americans the port of New Orleans and room to move west. Jefferson worried the Constitution didn't let him buy land, but he did it anyway. Later, deciding whether slavery could spread into this land led to the Missouri Compromise.
1819: Florida and new borders with Britain and Spain
Borders as of 22 February 1819
The Convention of 1818 with Britain set the northern border at 49° N, adding the Red River basin. In the Adams–Onís Treaty, signed in 1819 and in force in 1821, Spain gave up Florida, and the two countries drew a border all the way to the Pacific. The US had already taken West Florida, along the Gulf coast, in 1810 and 1813.
Secretary of State John Quincy Adams used these deals to make the US a continental power. The Louisiana Purchase's western edge shrank a little, because the US gave up its claim to Texas.
1845: Texas joins the Union
Borders as of 29 December 1845
Texas had broken away from Mexico in 1836. Congress annexed it in 1845, along with Texas's claim to land up to the upper Rio Grande.
Texas came in as a slave state, which deepened the fight over slavery's spread. Mexico had never accepted the loss of Texas, and the border dispute led to war the next year.
1846: The Oregon Treaty
Borders as of 15 June 1846
Britain and the US had shared the Oregon Country since 1818. The Oregon Treaty split it at 49° N, the line the border still follows.
Many Americans believed in Manifest Destiny, the idea that the US was meant to stretch across the continent. Polk got Oregon by compromise with Britain while getting ready for war with Mexico.
1848: The Mexican Cession
Borders as of 4 July 1848
In the Treaty of Guadalupe Hidalgo, which ended the Mexican–American War, Mexico gave up California and most of the Southwest. Together with Texas, that was about half of the land Mexico had claimed.
Gold was found in California the same year. Whether slavery would be allowed in all this new land split the country and led straight to the Compromise of 1850.
1867: Alaska
1898: Hawaii
Borders as of 7 July 1898
Congress annexed Hawaii by a joint resolution. American planters had overthrown the Hawaiian queen, Liliʻuokalani, in 1893.
The same year, the US won Puerto Rico, Guam and the Philippines from Spain. Americans argued over whether the country should rule distant lands at all. See the overseas map for those.
Where the borders come from
- Atlas of Historical County Boundaries: Historical States and Territories, 1783–2000, The Newberry Library. CC0 (public domain).
- Natural Earth coastlines, lakes and countries (1:50m), Natural Earth. Public domain.
What to keep in mind
- Each colored area is the land added on that date: the whole United States just after the change, minus the United States just before it, both from the Atlas. Where land changed hands twice, like the edge of the Louisiana Purchase that went to Spain in 1819 and came back with Texas, it's shown with the later change.
- The Atlas follows the borders the US claimed by law. It counts West Florida from 1804, when Congress claimed it, though the US only took control in 1810 and 1813.
- Small pieces from border surveys and treaties are grouped as “Smaller border settlements”. The 1842 treaty that settled Maine's northern border is not a separate step.
- Borders are from the Newberry Library's Atlas of Historical County Boundaries, which records every change to the day, with the law or treaty behind it. To keep the map quick to load, coastlines and borders are smoothed, so small bends and tiny islands are missing.