- Total 4,052 sq mi (10,490 km2)
- Land 3,568 sq mi (9,240 km2)
- Water 484 sq mi (1,250 km2)
Highest elevation 6,956 ft (2,120 m)
Population (April 1, 2010)
- Total 132,646
- Estimate (2017) 136,754
- Density 33/sq mi (13/km2)
The original inhabitants of the area now known as Humboldt County include the Wiyot, Yurok, Hupa, Karuk, Chilula, Whilkut, and the Eel River Athapaskan peoples, including the Wailaki, Mattole and Nongatl. Andrés de Urdaneta found the coast near Cape Mendocino then followed the coast south to Acapulco in 1565. Spanish traders made unintended visits to California with the Manila Galleons on their return trips from the Philippines beginning in 1565. Humboldt County was formed in 1853 from parts of Trinity County. The first recorded entry by people of European origin was a landing by the Spanish in 1775 in Trinidad.
The first recorded entry of Humboldt Bay by non-natives was an 1806 visit from a sea otter hunting party from Sitka employed by the Russian American Company. The hunting party included Captain Jonathan Winship, an American, and some Aleut hunters. The bay was not visited again by people of European origin until 1849 when Josiah Gregg’s party visited. In 1850, Douglas Ottinger and Hans Buhne entered the bay, naming it Humboldt in honor of the great naturalist and world explorer, Alexander von Humboldt, and the name was later applied to the county as a whole.
The area around Humboldt Bay was once solely inhabited by the Wiyot Indian tribe. One of the largest Wiyot villages, Tolowot, was located on Indian Island in Humboldt Bay. Founded around 900 BC, it contains a shell midden 6 acres (2.4 ha) in size and 14 feet (4.3 m) deep. It was the site of the February 26, 1860 massacre of the Wiyot people that was recorded by Bret Harte, then living in Union, now called Arcata. Between 60 and 200 Wiyot men, women, and children were murdered that night. Tolowot is now a restricted site and a National Historic Landmark.
State historic landmarks in Humboldt County include Arcata and Mad River Railroad, California’s First Drilled Oil Wells in Petrolia, Camp Curtis, Centerville Beach Cross, the City of Eureka, the town of Ferndale, Fort Humboldt, Humboldt Harbor Historical District, the Jacoby Building, The Old Arrow Tree, Old Indian Village of Tsurai, the Town of Trinidad, and Trinidad Head.
On February 5 and 6, 1885, Eureka’s entire Chinese population of 300 men and 20 women were expelled after a gunfight between rival Chinese gangs (tongs) resulted in the wounding of a 12-year-old boy and the death of 56-year-old David Kendall, a Eureka City Councilman. After the shooting, an angry mob of 600 Eureka residents met and informed the Chinese that they were no longer wanted in Eureka and would be hanged if they were to stay in town longer than 3 p.m. the next day. They were put on two steamships and shipped to San Francisco. No one was killed in the expulsion. Another Chinese expulsion occurred during 1906 in a cannery on the Eel River, in which 23 Chinese cannery workers were expelled after objections to their presence. However, some Chinese remained in the Orleans area, where some white landowners sheltered and purchased food for the Chinese mineworkers until after racial tension passed. Chinese did not return to the coastal cities until the 1950s.