Most of the 1st California was recruited from August to October 1861, with the exception of Company K, which was organized the following February.

Detachments from the camp captured Daniel Showalter's party near Warner's Ranch, November 20–29, 1861.

In December, 1861, five companies of the regiment were sent to Fort Yuma on the Colorado River and the others to various posts around Southern California.

[6] "The first or national color for Infantry shall be the same as that described for the garrison flag of the United States Army, with this exception: the name and number of the regiment shall be embroidered with silver on the centre strips.

"[6] The national flag presented to the regiment on 16 September 1861,[7][8] was made with Kibbe's orders in mind.

While on their trip back home near Fort Yuma one of the men died, soon his comrades draped black fabric around the flag as a sign of mourning.

[13] Company I received a "..magnificent silk American flag" made by the women of Marysville on July 4, 1861.

One of the regiment's flank markers is stored in UC Berkeley's Bancroft Library.