The Adams-Onís Treaty of 1819 resolved territorial disputes between the United States and Spain, leading to the acquisition of Florida and the establishment of the western boundary of the United States.
Manifest Destiny Explained
Manifest Destiny was the belief that it was the destiny of the United States to expand its territory across North America.
Louisiana Purchase (1803) Explained
The Louisiana Purchase was a land deal between the United States and France in which the U.S. acquired approximately 828,000 square miles of territory west of the Mississippi River for $15 million.