Oakland is a major West Coast port city in the U.S. state of California. Oakland is the third largest city in the San Francisco Bay Area, the eighth-largest city in California, and the 45th-largest city in the U.S. with a population of 413,775 . It serves as a trade center for the San Francisco Bay Area; its Port of Oakland is the busiest port for San Francisco Bay, all of Northern California, and fifth busiest in the United States. Incorporated in 1852, Oakland is the county seat of Alameda County. It is also the principal city of the Bay Area Region known as the East Bay. The city is situated directly across the bay, six miles east of San Francisco.