The 19th-century doctrine or belief that the expansion of the US throughout the American continents was both justified and inevitable.

The formal act of acquiring something (especially territory) by conquest or occupation.

The region ceded to the U.S. by Mexico in 1848 under the Treaty of Guadalupe Hidalgo after the Mexican-American War.

A proposal to ban slavery in any territory acquired from Mexico; it failed to pass the Senate.

The principle that the authority of a state and its government is created and sustained by the consent of its people, through their elected representatives (Rule by the People), who are the source of all political power.

Loyalty to the interests of one's own region or section of the country, rather than to the country as a whole.

A policy or practice of expansion and especially of territorial expansion by a nation.

A disagreement over the location of a boundary line between two or more entities.

A formally concluded and ratified agreement between countries.

Territory that is formally handed over to another country or entity by treaty or agreement.

US President who was a pro-expansionist Democrat, eager to acquire Mexican territory.

Led the Texan army to victory at San Jacinto, securing Texas's independence.

A legendary figure who died defending the Alamo.

The U.S. diplomat who negotiated the Treaty of Guadalupe Hidalgo.

The Mexican general and president during the Texas Revolution and the Mexican-American War.

A U.S. general during the Mexican-American War who later became President of the United States.

A U.S. general who led the invasion of Mexico City during the Mexican-American War.

A U.S. Congressman who proposed the Wilmot Proviso, which aimed to ban slavery in territories acquired from Mexico.

A U.S. general who led forces to capture Santa Fe and California during the Mexican-American War.

A U.S. diplomat sent to Mexico to negotiate the purchase of California and New Mexico before the Mexican-American War.

A 13-day siege where Texan defenders were defeated by Mexican forces; it became a symbol of Texan resistance.

The execution of over 400 Texan prisoners by Mexican forces, fueling Texan rage.

Sam Houston led the Texan army to a decisive victory, securing Texas's independence.

Texan settlers declared independence from Mexico, leading to battles like the Alamo, Goliad, and San Jacinto.

The treaty that officially ended the Mexican-American War in 1848.

A war fought between the United States and Mexico from 1846 to 1848, resulting in a US victory and significant territorial gains for the US.

The incorporation of the Republic of Texas into the United States in 1845, which Mexico viewed as an act of aggression.

A period of mass migration to California starting in 1848 after gold was discovered, leading to rapid population growth and economic changes.

A series of laws passed by the United States Congress in September 1850 that dealt with the issue of slavery and territorial expansion.

A law passed in 1854 that allowed residents of Kansas and Nebraska to decide whether to allow slavery, leading to violence and political turmoil.