Fort Ross is a former Russian establishment on the west coast of North America in what is now Sonoma County, California. It was the hub of the southernmost Russian settlements in North America from 1812 to 1841. Notably, it was the first multi-ethnic community in northern California, with a combination of Native Californians, Native Alaskans, Russians, Finns, and Swedes. It has been the subject of archaeological investigation and is a California Historical Landmark, a National Historic Landmark, and on the National Register of Historic Places. It is part of California's Fort Ross State Historic Park.

Sonoma County is located in the U.S. state of California. As of the 2020 United States Census, its population was 488,863. Its seat of government and largest city is Santa Rosa.