Inyo County is a county in the eastern central part of the U.S. state of California, located between the Sierra Nevada and the state of Nevada. In the 2020 census, the population was 19,016.The county seat is Independence.Inyo County is on the east side of the Sierra Nevada and southeast of Yosemite National Park in Central California. It contains the Owens River Valley; it is flanked to the west by the Sierra Nevada and to the east by the White Mountains and the Inyo Mountains. With an area of 10,192 square miles (26,400 km2), Inyo is the second-largest county by area in California, after San Bernardino County. Almost half of that area is within Death Valley National Park. However, with a population density of 1.8 people per square mile, it also has the second-lowest population density in California, after Alpine County.

Present-day Inyo county has been the historic homeland for thousands of years of the Mono, Timbisha, Kawaiisu, and Northern Paiute Native Americans. The descendants of these ancestors continue to live in their traditional homelands in the Owens River Valley and in Death Valley National Park. Worse, the portion north of the 37th parallel had been claimed by Nevada Territory (later the state of Nevada) as part of its westernmost border from 1861 to 1866.

Further information: History of California through 1899

Inyo County was formed in 1866 out of the territory of the unorganized Coso County, which had been created on April 4, 1864, from parts of Mono County and Tulare County. It acquired more territory from Mono County in 1870 and Kern County and San Bernardino County in 1872.

For many years it has been commonly believed that the county derived its name from the Mono tribe’s name for the mountains in its former homeland. Actually the name came to be thought of, mistakenly, as the name of the mountains to the east of the Owens Valley when the first whites there asked the local Owens Valley Paiutes for the name of the mountains to the east. They responded that that was the land of Inyo. They meant by this that those lands belonged to the Timbisha tribe headed by a man whose name was Inyo. Inyo was the name of the headman of one of the Timbisha bands at the time of contact when the first whites, the Bennett-Arcane Party of 1849, wandered, lost, into Death Valley on their expedition to the goldfields of western California. The Owens Valley whites misunderstood the reference and thought that Inyo was the name of the mountains when actually it was the name of the chief, or headman, of the tribe that had those mountains as part of their homeland. In Timbisha, ɨnnɨyun means “it’s (or he’s) dangerous”.

To supply the growing City of Los Angeles, water was diverted from the Owens River into the Los Angeles Aqueduct in 1913. The Owens River Valley cultures and environments changed substantially. From the 1910s to 1930s the Los Angeles Department of Water and Power purchased much of the valley for water rights and control. In 1941 the Los Angeles Department of Water and Power extended the Los Angeles Aqueduct system farther upriver into the Mono Basin.