When and how was most of territory acquired?

The United States acquired most of its territory in the 19th century through a combination of purchases, treaties, and military conquests. The largest single acquisition was the Louisiana Purchase of 1803, which doubled the size of the country and gave the United States control of the Mississippi River and much of the Great Plains. Other major acquisitions included the Florida Purchase of 1819, the Texas Annexation of 1845, the Oregon Territory Treaty of 1846, and the Mexican Cession of 1848. These acquisitions gave the United States its current continental boundaries, except for Alaska, which was purchased from Russia in 1867.

Here is a timeline of the major territorial acquisitions of the United States:

* 1783: Treaty of Paris - The United States gains independence from Great Britain and control of the thirteen original colonies.

* 1803: Louisiana Purchase - The United States purchases the Louisiana Territory from France, which doubles the size of the country.

* 1819: Florida Purchase - The United States purchases Florida from Spain.

* 1845: Texas Annexation - The United States annexes the Republic of Texas.

* 1846: Oregon Territory Treaty - The United States and Great Britain agree on the boundary of the Oregon Territory, which includes the present-day states of Oregon, Washington, and Idaho.

* 1848: Mexican Cession - The United States gains control of the Southwest and California from Mexico following the Mexican-American War.

* 1867: Alaska Purchase - The United States purchases Alaska from Russia.

In addition to these major acquisitions, the United States also acquired smaller territories through various treaties and cessions, such as the Gadsden Purchase of 1853 and the annexation of Hawaii in 1898.