Chronicle the rapid territorial expansion of the U.S. across the North American continent.
Identify the specific treaties, purchases, and wars that yielded new territories.
Understand how Manifest Destiny accelerated sectional tensions over the expansion of slavery.
Key Concept
Manifest Destiny was the widely held belief in the 19th-century United States that American settlers were destined to expand across North America.
Tags
US HistoryManifest DestinyExpansionTreaties
Territorial Acquisition
Current Era1783
Continental StatusOriginal 13 + NW
Expansion Events
Original United States (1783) Established by the Treaty of Paris ending the Revolutionary War. Includes the original 13 colonies and the Northwest Territory stretching to the Mississippi River.
Louisiana Purchase (1803) Bought from France (Napoleon) for $15 million by Thomas Jefferson. Doubled the size of the nation, granting full control of the Mississippi River and Port of New Orleans.
Adams-Onís Treaty (1819) Spain ceded Florida to the U.S. and established a clear boundary between the Louisiana territory and New Spain.
Texas Annexation (1845) The Republic of Texas willingly joined the Union as a slave state, angering Mexico and setting the stage for the upcoming Mexican-American War.
Oregon Treaty (1846) Compromise with Great Britain dividing the Oregon Country at the 49th parallel, fulfilling Polk's expansionist campaign ("54°40' or Fight") without invoking war.
Mexican Cession (1848) Treaty of Guadalupe Hidalgo ending the Mexican-American War. Mexico surrendered massive territory (CA, NV, UT, AZ, NM) for $15M. Sparked intense debate over the expansion of slavery (Wilmot Proviso).
Gadsden Purchase (1853) A small strip of land in southern AZ/NM bought from Mexico for $10M specifically to build a southern transcontinental railroad.
Quick Quiz
Which addition of territory most directly ignited the fiery debates over slavery that led to the Compromise of 1850?