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 bay was not visited again by people of European origin until 1849. In 1850, Douglas Ottinger and Hans Buhne entered the bay, naming it Humboldt in honor of the great naturalist and world explorer, Baron Alexander von Humboldt, and the name was later applied to the county as a whole.

NameNational LandmarkState LandmarkPoint of InterestOther Designation
Trinidad HeadN/A146N/AN/A
Fort HumboldtN/A154N/AN/A
The Old Arrow TreeN/A164N/AN/A
Centerville Beach CrossN/A173N/AN/A
Camp CurtisN/A215N/AN/A
Town of TrinidadN/A216N/AN/A
City of EurekaN/A477N/AN/A
California's First Drilled Oil WellsN/A543N/AN/A
Jacoby BuildingN/A783N/AN/A
Old Indian Village of TsuraiN/A838N/AN/A
Arcata and Mad River Rail Road CompanyN/A842N/AN/A
Humboldt Harbor Historical DistrictN/A882N/AN/A