Founded April 8, 1850, Trinidad is the oldest town on the Northern California coast. During the 1850s, it served as a vital supply link between ships anchored at Trinidad Bay and miners in the Klamath, Trinity, Salmon River, and Gold Bluff mines. It was the county seat of Klamath County (now disbanded) from 1851 to 1854, but its population declined as Eureka and other area port cities developed.

California Registered Historical Landmark No. 216

Plaque placed by the State Department of Parks and Recreation in cooperation with the Ancient and Honorable Order of E Clampus Vitus, Eureka Chapter #101, June 7, 1981.