The U.S.–Mexican War (1846–1848) marked a decisive moment in the territorial and political transformation of North America. The conflict was triggered by the U.S. annexation of Texas (1845) and a disputed southern boundary, claimed by the United States at the Río Grande and by Mexico at the Nueces River, under President James K. Polk (in office 1845–1849). Rooted in expansionist ideology (Manifest Destiny), demographic pressure, and unresolved legacies of Mexican independence, the war rapidly escalated into a full-scale interstate conflict between two unequal powers.
Military operations unfolded across multiple theaters, revealing the growing reach of U.S. land and naval forces. Campaigns along the northern frontier secured Texas, while western expeditions and naval control dismantled Mexican authority in California and New Mexico. A final amphibious landing on the Gulf Coast opened the route to central Mexico, culminating in the occupation of Mexico City (1847) and forcing negotiations. The Treaty of Guadalupe Hidalgo (2 February 1848) ended the war, confirming the Río Grande as the Texas border and transferring roughly 55% of Mexico’s pre-war territory to the United States. The conflict reshaped continental boundaries, intensified debates over slavery’s expansion, and left a lasting legacy of political instability and resentment in U.S.–Mexican relations.
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APA Style
Netchev, S. (2026, January 09). Map of the US-Mexican War of 1846-1848. World History Encyclopedia. https://www.worldhistory.org/image/20645/map-of-the-us-mexican-war-of-1846-1848/
Chicago Style
Netchev, Simeon. "Map of the US-Mexican War of 1846-1848." World History Encyclopedia, January 09, 2026. https://www.worldhistory.org/image/20645/map-of-the-us-mexican-war-of-1846-1848/.
MLA Style
Netchev, Simeon. "Map of the US-Mexican War of 1846-1848." World History Encyclopedia, 09 Jan 2026, https://www.worldhistory.org/image/20645/map-of-the-us-mexican-war-of-1846-1848/.
