United States Nevada Carson County
Organized as an original county 17 January 1854 as part of Utah Territory. Carson County was created from the far western parts of Tooele, Juab, Millard, and Iron counties. It was enlarged in 1856, then discontinued in 1857. It was reorganized as part of Utah in 1859. Included all of present-day Nevada between 118° and 120° west longitude. May also have included the Great Basin parts of eastern California.
Discontinued 2 March 1861 when Nevada Territory was created. Became part of Douglas, Lyon, Ormsby, Storey, Churchill, Pershing, Humboldt, and Washoe counties, and Carson City (independent city).