Acquired from England by the Treaty of Paris at the end of the American Revolution

Louisiana Purchase (1803) purchased from France that doubled the size of the United States

The U.S. eventually forced Spain to part with Florida in 1819. Formal U.S. occupation began in 1821, was organized as a U.S. territory in 1822, and was admitted into the Union in 1845.

After the Texas Revolution in 1845, the United States annexed (captured) Texas, which had been part of Mexico

Treaties with Britain in 1818 and 1842 filled in other very small portions of the United States along the northern border.

The United States acquired the Oregon Territory from England in 1846 through negotiations

Acquired by conquest in 1848 from Mexico at the end of the Mexican-American War

Gadsden Purchase (1853) was a purchase from Mexico in 1853 completed the mainland United States