United States annexes the Republic of Texas
Labels: Republic of, United StatesTexas was formally admitted as the 28th U.S. state, intensifying the U.S.–Mexico boundary dispute (Rio Grande vs. Nueces River) that helped set the stage for war.
Mexican–American War and U.S. Territorial Expansion (1846–1848)
Battle of Palo Alto opens major combat
Labels: Battle of, Zachary TaylorThe first major battle of the war occurred on disputed ground near present-day Brownsville, Texas; U.S. forces under Zachary Taylor defeated Mexican forces under Mariano Arista.
Battle of Resaca de la Palma follows
Labels: Resaca de, Zachary TaylorFought the day after Palo Alto, this U.S. victory forced Mexican forces to withdraw south of the Rio Grande, consolidating U.S. control in the contested border area.
U.S. Congress declares war on Mexico
Labels: U S, James KAfter President Polk’s request citing clashes along the Rio Grande, Congress passed the act recognizing that a state of war existed between the two countries.
Wilmot Proviso introduced in Congress
Labels: Wilmot Proviso, David WilmotRep. David Wilmot proposed banning slavery in any territory acquired from Mexico, foreshadowing the sectional conflict that U.S. territorial expansion would intensify.
Battle of Monterrey ends with capitulation
Labels: Battle of, Zachary TaylorU.S. forces under Zachary Taylor captured Monterrey after hard urban fighting; the battle’s outcome secured a key northern Mexican city for the United States.
Treaty of Cahuenga ends fighting in California
Labels: Treaty of, John CAn agreement between U.S. forces (John C. Frémont) and Californio forces (Andrés Pico) established a ceasefire in Alta California, effectively ending major combat there.
Battle of Buena Vista fought in northern Mexico
Labels: Battle of, Antonio LZachary Taylor’s army fought Santa Anna’s larger force at Buena Vista/La Angostura; the battle became a major U.S. political and military touchstone.
Siege of Veracruz begins amphibious campaign
Labels: Siege of, Winfield ScottWinfield Scott’s army landed and besieged Veracruz, a crucial port for supplying an advance into central Mexico; the city surrendered later in March.
Battle of Cerro Gordo breaks Mexican defenses
Labels: Battle of, Winfield ScottScott’s forces outflanked Santa Anna’s fortified position at a mountain pass near Xalapa, opening the route inland toward Puebla and ultimately Mexico City.
Battles of Contreras and Churubusco
Labels: Contreras, ChurubuscoAs U.S. forces approached Mexico City, they defeated Mexican forces at Contreras (Padierna) and then at Churubusco, pushing the campaign to the capital’s outskirts.
Battle of Molino del Rey fought near Mexico City
Labels: Molino del, Mexico CityA costly engagement on the western edge of the capital area weakened Mexican positions during Scott’s final operations against Mexico City’s defenses.
Battle of Chapultepec leads to Mexico City’s fall
Labels: Battle of, Chapultepec CastleU.S. forces captured Chapultepec Castle after bombardment and assault, opening approaches into Mexico City and marking a decisive turning point in the campaign.
U.S. forces enter and occupy Mexico City
Labels: Occupation of, Winfield ScottWinfield Scott’s army entered Mexico City, effectively ending major military operations and shifting the conflict’s outcome to diplomacy and treaty terms.
Treaty of Guadalupe Hidalgo signed
Labels: Treaty of, MexicoNegotiators concluded the treaty ending the war: Mexico recognized the Rio Grande boundary for Texas and ceded vast territories to the United States in exchange for payment and assumption of claims.
U.S. Senate advises ratification with amendments
Labels: U S, Treaty ratificationThe U.S. Senate voted to ratify the Treaty of Guadalupe Hidalgo with amendments, a key step in formally ending the war and finalizing U.S. territorial gains.
Ratifications exchanged at Querétaro
Labels: Quer taro, Ratification exchangeThe United States and Mexico exchanged treaty ratifications at Querétaro, completing the bilateral approval process required for the treaty to take effect.
Treaty of Guadalupe Hidalgo proclaimed
Labels: Treaty proclamation, United StatesThe treaty was formally proclaimed, marking the official end of the Mexican–American War and establishing the legal framework for U.S. governance in the newly acquired territories.
Timeline
18451846184718471848
Mexican–American War and U.S. Territorial Expansion (1846–1848)
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