Klamath County, California

Klamath County was a county of California from 1851 to 1874. During its existence, the county seat moved twice and several counties were carved from its territory. It was formed from the northwestern portion of Trinity County, and originally included all of the northwestern part of the state, from the Mad River in the south to Oregon in the north, from the Pacific Ocean in the west to the middle of what is now Siskiyou County in the east.

The original county seat was Trinidad, on the county's southwestern coast. In 1854 the county seat was moved to Crescent City, because of its larger population. But the western portion of the county was unrepresentative of the mining interests in the eastern portion of the county, and so, in 1856, the county seat was moved inland, to Orleans Bar.

In 1857, Del Norte County, including Crescent City, was split off from Klamath County.

The county's economy was never healthy. In 1874 it was finally abolished, divided into Siskiyou and Humboldt Counties.