What part did california play in the war between the states?
California sided with the Union, but most Southern Californians sympathized with the South. However, Southern Californians had other things on their minds besides war. Massive floods in 1862 were followed by a severe drought that devastated the cattle industry, which dominated Southern California's economy at the time.
In 1862, the war came perilously close to California when the Confederate Army came within about 80 miles of the border, briefly making contact with Union troops somewhere near what is now Dateland, Ariz. The westernmost land battle of the war was fought at Picacho Peak, about 200 miles east of the border, just west of Tucson.
“California’s involvement in the American Civil War included sending gold east, recruiting volunteer combat units to replace regular forces in territories of the Western United States, maintaining and building numerous camps and fortifications, suppressing secessionist activity (many of these secessionists went east to fight for the confederacy) and securing the New Mexico Territory against the Confederacy”
https://en.wikipedia.org/wiki/California_in_the_American_Civil_War