Bakersfield is a city in Kern County, California, United States. It is the county seat and largest city of Kern County. The city covers about 151 sq mi near the southern end of the San Joaquin Valley and the Central Valley region. Bakersfield's population as of the 2020 census was 403,455, making it the 48th-most populous city in the United States of America and the 9th-most populous city in California.