Arcata is a city adjacent to the Arcata Bay (northern) portion of Humboldt Bay in Humboldt County, California, United States. At the 2020 census, Arcata's population was 18,857. Arcata was first founded in 1850 as Union, was officially established in 1858, and was renamed Arcata in 1860. It is located 280 miles (450 km) north of San Francisco, and is home to California State Polytechnic University, Humboldt. Arcata is also the location of the Arcata Field Office of the Federal Bureau of Land Management, which is responsible for the administration of natural resources, lands and mineral programs, including the Headwaters Forest, on approximately 200,000 acres (810 km2) of public land in Northwestern California.