- January 2 - Battle of Santa Clara.
- January 8 - Battle of Rio San Gabriel (Los Angeles).
- January 9 - Battle of La Mesa (Los Angeles).
- January 24 - Battle of La Canada.
- January 24 - Battle of Mora.
- January 29 - Battle of Embudo Pass.
- February 3-4 - Siege of Pueblo de Taos.
- February 23 - Battle of Buena Vista - General Taylor's 4,700 soldiers withstand
the attack of Santa Anna's 20,000 Mexicans. The Mexicans withdraw.
- February 28 - Battle of the Sacramento.
- March 9-29 - Siege of Veracruz.
- March 27 - General Winfried Scott captures the fort on the harbor of Veracruz.
- April 18 - General Scott, with 800 men, drives 15,000 Mexicans from the pass of
- June 6 - Affair at Las Vegas, New Mexico.
- August 19-20 - Battles of Contreras and Churubusco.
- September 8 - Battle of El Molino del Rey.
- September 13 - Battle of Chapultepec.
- September 13-15 - Battles for Mexico City.
- September 14 - American troops enter Mexico City.
- September 14-Oct. 12 - Siege of Puebla.
- October 5 - Huamantla Affair.
- October 19 - Atlixco Affair.
- February 2- Treaty of Guadaloupe Hidalgo