President:
Pres: James K. Polk
Pres: Zachary Taylor elected over Lewis Cass
General
- Culture: Meeting in Seneca Falls New York calls for Women's rights
- Land: Treaty of Guadalupe Hildago ends the war between Mexico and the U.S., incorporating CA, NV, UT, AZ (most) and parts of NM, CO, WY and TX
- Medicine: Cholera outbreak for next 18 years
- Military: End of Mexican-American War with treaty of Guadalupe Hidalgo
- Natives: Cayuse War until 1855
- Politics: Free Soil Party organized to stop spread of slavery
- Religion: Spiritualism becomes popular in US
- Science: American Association for Advancement of Science established
East
- New York: Cholera outbreak kills 4000 in New York City
First women's rights convention in Seneca Falls
NY News Agency founded (after 1856 the Associated Press)
Midwest
- Illinois: Chicago gets first rail service
- Wisconsin: Statehood as #30
Blacks disenfranchised
South
West and Pacific
- General: End of Mexican War
- California: Treaty of Guadelupe Hidalgo gives California to US
Gold discovered at Sutter's Mill
- New Mexico: Treaty of Guadelupe Hidalgo gives New Mexico to US
- Oregon: Named US territory