Trinity County was founded on February 18,1850 as one of the original 27 counties (administered by Shasta County until 1851). The county was named for the Trinity River, named in 1845 by Major Pearson B. Reading, who was under the mistaken impression that the stream emptied into Trinidad Bay. Trinity is the English version of Trinidad. The Trinity County seat is located in Weaverville. Bordering Trinity County is Mendocino County (south), Humboldt County (west), Siskiyou County (north), Shasta County (east), Tehama County (southeast).
Courthouse History: After an 1860 grand jury reported that "bed bugs had invaded the offices of the sheriff and the clerk, had defiled the records, and had even attacked a judge on the bench," Trinity County supervisors began to consider moving from the old Weaverville courthouse, which at the time was being shared with the Masonic Lodge. In 1865 the county purchased the existing brick building that then housed offices, hotel rooms and the Apollo Saloon which boasted the first piano in the county. The courthouse is the second oldest courthouse still in use in the state of California and serves as a cornerstone landmark in Weaverville's Historic District.