Conquest of California

Belligerents

United States
California Republic (until July 9, 1846)

MexicoCommanders and leaders

Units involved

Units

California Republic
Bear Flag Rebels
United States
California Battalion
Army of the West
Naval units
Pacific Squadron
Occupation units
Mormon Battalion
1st Regiment of New York Volunteers

Units

Mexico
Castro Battalion
P. Pico Battalion
Flores Battalion
Local Town Militias
Cavalry units
A. Pico Lanceros
Lugo Lanceros
Carrillo Lanceros

Strength

USA

Initial strength:

30–300 militia
Horses and Mules
Native American Scouts

Peak strength:

2,000+ personnel (1847)

Mexico

Initial strength:

- 260–500 militiamen
- 1 swivel Canon
Horses and Mules

Peak strength:

500 personnel (Jan. 1847)

Casualties and losses

California Republic:
- 1–2 killed
- 3–7 wounded
- 2 captured or missing
United States:
- ~35–40 killed
- ~53–64 wounded
- 25 captured or missing

Total: 64–75
10–15 killed
50–55 wounded
4–5 captured

The Conquest of California, also known as the Conquest of Alta California or the California Campaign, was a military campaign during the Mexican–American War carried out by the United States in Alta California (modern-day California), then part of Mexico, lasting from 1846 to 1847, and ending with signing of the Treaty of Cahuenga by military leaders from both the Californios and Americans.