•
Branciforte County was the original name of
Santa Cruz County in 1850. The reference was to the 1797 town of
Branciforte. •
Klamath County was created in 1851 from the northern half of Trinity County. Part of the county's territory went to Del Norte County in 1857, and in 1874 the remainder was divided between Humboldt and Siskiyou counties. • Pautah County, California was created in 1852 out of territory which, the state of California assumed, was to be ceded to it by the
United States Congress from territory in what is now the state of
Nevada. When the cession never occurred, the
California State Legislature officially abolished the never-organized county in 1859. •
Buena Vista County was created in 1855 by the California State Legislature out of the southeastern territory of Tulare County on the west of the
Sierra Nevada but was never officially organized. The south of Tulare County was later organized as
Kern County in 1866, with additions from Los Angeles and San Bernardino counties. •
Coso County was created in 1864 by the California State Legislature out of territory of Mono County and Tulare County on the east slope of the Sierra Nevada but was never officially organized. The region was later organized in 1866 as
Inyo County with additions from Los Angeles and San Bernardino counties. •
Roop County, Nevada encompassed much of
Lassen County, including the
Honey Lake Valley and the community of
Susanville, California; ambiguous organic legislation of
Nevada Territory led to confusion about the geographic extent of Nevada's western border. This was later clarified, with the portions of Roop County in California being assigned to Lassen County; the remaining, sparsely portions of Roop County were eventually combined with
Washoe County, Nevada. == Proposed counties ==