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Louisiana Purchase
Land deal between the US and France where the US acquired about 827,000 square miles of land west of the Mississippi river for $15 million -
Lewis and Clark Expedition
First American expedition to cross the western portion of the United States. It began near St. Louis, made its way westward, and passed through the Continental Divide of the Americas to reach the Pacific coast. President Thomas Jefferson commissioned the expedition shortly after the Louisiana Purchase in 1803 to explore and to map the newly acquired territory, to find a practical route across the western half of the continent, and to establish an American presence in this territory. -
Acquisition of Florida
After years of negotiations, Secretary of State John Quincy Adams achieved a diplomatic coup with the signing of the Florida Purchase Treaty, which officially put Florida into U.S. hands at no cost beyond the U.S. assumption of some $5 million of claims by U.S. citizens against Spain. -
Missouri Compromise
An effort by Congress to defuse the sectional and political rivalries triggered by the request of Missouri for admission as a state in which slavery would be permitted. At the time, the United States contained twenty-two states, evenly divided between slave and free. -
Battle of the Alamo
A pivotal event in the Texas Revolution. Following a 13-day siege, Mexican troops under President General Antonio López de Santa Anna launched an assault on the Alamo Mission near San Antonio de Béxar, killing the Texian defenders. Santa Anna's cruelty during the battle inspired many —both Texas settlers and adventurers from the United States—to join the Texian Army. Buoyed by a desire for revenge, they defeated the Mexican Army at the Battle of San Jacinto, in 1836, ending the revolution. -
Trail of Tears
The Trail of Tears was a series of forced relocations of Native Americans in the United States from their ancestral homelands in the Southeastern United States, to areas to the west (usually west of the Mississippi River) that had been designated as Indian Territory. The forced relocations were carried out by government authorities. The natives suffered from exposure, disease, and starvation while on their route of sometimes 100's of miles, and many died before reaching their destinations. -
Manifest Destiny
Manifest Destiny, a phrase coined in 1845, expressed the philosophy that drove 19th-century U.S. territorial expansion. Manifest Destiny held that the United States was destined—by God, its advocates believed—to expand its dominion and spread democracy and capitalism across the entire North American continent. -
Annexation of Texas
Annexation of the Republic of Texas into the United States of America, which was admitted to the Union as the 28th state on December 29, 1845. -
Acquisition of Oregon
The Oregon boundary dispute between the U.S. and Britain was settled with the signing of the Oregon Treaty. The British gained sole possession of the land north of the 49th parallel and all of Vancouver Island, with the United States receiving the territory south of that line. -
Donner Party
A group of American pioneers that set out for California in a wagon train in May 1846. Departing from Independence, Missouri, they were delayed by a series of mishaps and mistakes, and spent the winter of 1846–47 snowbound in the Sierra Nevada. The party has come to popular attention due to some of the pioneers resorting to cannibalism to survive. -
Discovery of Gold in California
The California Gold Rush began on January 24, 1848, when gold was found by James W. Marshall at Sutter's Mill in Coloma, California. The news of gold brought approximately 300,000 people to California from the rest of the United States and abroad. -
Treaty of Guadalupe-Hidalgo
The Mexican-American war officially ended with the signing in Mexico of the Treaty of Guadalupe Hidalgo. The treaty added an additional 525,000 square miles to United States territory, including the land that makes up all or parts of present-day Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming. -
Compromise of 1850
The Compromise of 1850 was a package of five separate bills passed by the United States Congress in September 1850, which defused a four-year political confrontation between slave and free states on the status of territories acquired during the Mexican–American War. -
Gadsden Purchase
The Gadsden Purchase, or Treaty, was an agreement between the United States and Mexico, in which the United States agreed to pay Mexico $10 million for a 29,670 square mile portion of Mexico that later became part of Arizona and New Mexico. Gadsden’s Purchase provided the land necessary for a southern transcontinental railroad and attempted to resolve conflicts that lingered after the Mexican-American War. -
Kansas Nebraska Act
The Kansas-Nebraska Act was passed by the U.S. Congress on May 30, 1854. It allowed people in the territories of Kansas and Nebraska to decide for themselves whether or not to allow slavery within their borders. The Act served to repeal the Missouri Compromise of 1820 which prohibited slavery north of latitude 36°30´.