1846 – 1848
A war of territorial expansion begun after the United States annexed Texas and President James K. Polk sent troops into the disputed land between the Nueces River and Rio Grande. Following a clash there, Congress declared war in May 1846. U.S. armies invaded northern and central Mexico and occupied Mexico City; the Treaty of Guadalupe Hidalgo ended the war under occupation and transferred an enormous territory to the United States, while promising rights to Mexican residents that were often eroded afterward.
Chapter-by-chapter narrative with maps, primary sources, and key events.
Explore battles on a live map with a timeline slider and territory overlays.
Deep-dive into every major engagement — commanders, casualties, significance.
Biographical flip cards with real portraits, facts, and full biography pages.
Trace each figure's full life journey — birth, education, battles, and death — on a live map.
Scroll-driven visualization of casualties — each dot a thousand lives.
Weapons, war machines, and the military innovations that defined how this conflict was fought.
Cause-and-effect chains tracing the war's long shadow on history.
War crimes, massacres, and the darkest chapters of this conflict — documented for history.
A war of territorial expansion begun after the United States annexed Texas and President James K. Polk sent troops into the disputed land between the Nueces River and Rio Grande. Following a clash there, Congress declared war in May 1846. U.S. armies invaded northern and central Mexico and occupied Mexico City; the Treaty of Guadalupe Hidalgo ended the war under occupation and transferred an enormous territory to the United States, while promising rights to Mexican residents that were often eroded afterward.
The Mexican-American War was fought from 1846 to 1848.
The Mexican-American War was fought between United States and Mexico.
An estimated 54,283 people died in The Mexican-American War, including roughly 29,283 military and 25,000 civilian deaths. Figures are scholarly estimates and vary by source.
Major engagements included Battle of Churubusco, Capture of Mexico City, Battle of Molino del Rey, and Battle of Chapultepec.