The United States was formed in 1776 by the federation of 13 colonies on the East Coast. Since then, it has grown:
- 1783. The Treaty of Paris (formally ending the Revolutionary War and granting to the United States all of the area east of the Mississippi River, north of Florida, and south of Canada).
- 1803. The Louisiana Purchase.
- 1819. The Adams–Onís Treaty, adding Florida.
- 1820. Maine.
- 1825. “Seward’s Folly.” Purchase of Alaska from Russia.
- 1845. Texas Annexation.
- 1846. Oregon Territory.
- 1848. The Mexican-American War. The Treaty of Guadalupe. The “Mexican Cession” added Arizona, California, Nevada, New Mexico, Utah, and western Colorado.
- 1853. Gadsden Purchase adding southern Arizona and southern New Mexico.
- 1898. Hawaii Annexation.
- 1899. The Tripartite Convention partitioned the Samoan Islands into two and the eastern island group became American Samoa.
- 1917. The Treaty of the Danish West Indies. The U.S. purchased the American Virgin Islands.
- And without getting into too much detail, the U.S. also acquired many Pacific Ocean islands, while other islands were won during WWII.
