Williams is a city in Colusa County, California. The population was 5,643 at the time of the 2010 census, up from 3,670 at the 2000 census.

Colusa County is a county located in the U.S. state of California. As of the 2020 census, the population was 21,839. The county seat is Colusa. It is in the northern Sacramento Valley, northwest of the state capital, Sacramento.