Mariposa County () is a county in the U.S. state of California. As of the 2020 U.S. census, the population was 17,131. The county seat is Mariposa. The county lies in the western foothills of the Sierra Nevada, north of Fresno, east of Merced, and southeast of Stockton. The eastern portion of the county encompasses the principal area of Yosemite National Park.
Mariposa County is one of only three counties in California that does not include any incorporated cities, along with Alpine and Trinity counties. The county includes 17 communities recognized as census-designated places for statistical purposes. It has no traffic signals anywhere within its borders.
thumb|alt=White wooden courthouse with clock tower surrounded by trees|The [[Mariposa County Courthouse, built in 1854, is California's oldest court of law in continuous operation.
At the time of statehood in 1850, Mariposa County was the largest of the original 27 California counties by area, covering over or about one-fifth of the state. It became known as the "Mother of Counties" because its territory was ceded over time to eventually form all of present-day Merced, Madera, Fresno, Tulare, Kings, and Kern counties; and parts of present-day San Benito, Mono, Inyo, San Bernardino, and Los Angeles counties.
The county's original seat was a now-nonexistent hamlet known as Agua Fria (Spanish for "cold water"), about west of present-day Mariposa on Agua Fria Road. The county seat then moved to Mariposa in 1854, resulting in the construction of the Mariposa County Courthouse, California's oldest court of law in continuous operation, whose grounds occupy an entire block. The courthouse, fronted by Bullion Street with Jones Street to the rear and 9th and 10th Streets on either side, is depicted on the Mariposa County Seal.
Indigenous peoples
The territory now comprising Mariposa County was inhabited by the Southern Sierra Miwok, whose villages occupied the foothills and lower mountain slopes along the Merced, Tuolumne, and Chowchilla river drainages. The Yokuts occupied the San Joaquin Valley floor and adjacent foothills; early Spanish and American accounts applied the name "Mariposas" to the Yokuts bands near the creek. The two groups maintained trade relationships across the foothill boundary.
During the Gold Rush, the rapid expansion of mining camps into indigenous territories produced violent conflict. In December 1850, Governor John McDougal authorized the Mariposa Battalion, a state militia unit mustered on February 12, 1851, under Major James D. Savage. The battalion's pursuit of the Ahwahnechee leader Tenaya into the Sierra Nevada resulted in the first documented entry by non-indigenous people into Yosemite Valley, in March 1851. The conflict, known as the Mariposa War, ended with Tenaya's capture and the forced removal of Ahwahnechee to a reservation on the Fresno River.
Gold Rush
thumb|upright=0.65|alt=Gold specimen with crystalline structures on dark matrix|Specimen gold from the Mockingbird mine
Mariposa County lies at the southern end of California's Mother Lode region. During the California Gold Rush, large quantities of gold were found and extracted, first in local stream beds and later in hard-rock mines. One of the most notable beneficiaries was John C. Frémont, explorer and 1856 Republican presidential candidate, for whom the local hospital and Charles Street (more commonly known as "Highway 140") are named. Jessie Street in Mariposa is named for Frémont's wife, Jessie Benton Frémont, who accompanied him on extended visits to Las Mariposas between 1849 and 1861.
thumb|alt=Row of Gold Rush-era buildings along a main street in Coulterville|Buildings along the Coulterville Main Street Historic District
Many aspects of the area's mining history are depicted in exhibits at two local museums: the Mariposa History Museum in the town of Mariposa, and the California Mining and Mineral Museum at the Mariposa Fairgrounds, southeast of Mariposa on State Route 49.
The Coulterville Main Street Historic District, listed on the National Register of Historic Places in 1982, preserves 24 Gold Rush-era buildings along the main street of Coulterville.
Two small gold mines in Mariposa County, the Mockingbird mine and the Colorado Quartz mine, intermittently produce world-class specimens of crystalline gold for mineral collectors. "Specimens from these occurrences commonly have bright luster and rich color, with well-developed crystals in unusual and attractive arrangements." The best-known example is "The Dragon", on display at the Houston Museum of Natural Science.
Among the county's Gold Rush-era settlements, Cat Town gave its name to the Cat Town Mining District, a gold-bearing area in the western Sierra Nevada foothills catalogued by the California Division of Mines and Geology.
Geography
According to the United States Census Bureau, the county has a total area of , of which is land and (1.0%) is water. The county extends:
- West from the western foothills of the Sierra Nevada to the edge of the Central Valley
- East into the Sierra including Yosemite Valley and a portion of the Cathedral Range
Water
Much of the Merced River's course lies within the county, including its whitewater runs through Yosemite and the Merced River Canyon. The canyon supports the only known population of the limestone salamander (Hydromantes brunus), a species endemic to a short stretch of the Merced River in Mariposa County. Becknell Creek is located near the historic community of Ben Hur.
There are several lakes within the county, including Lake McClure, Lake McSwain, Merced Lake, and Tenaya Lake.
Adjacent counties
- Tuolumne County – north
- Mono County – east
- Madera County – southeast
- Merced County – southwest
- Stanislaus County – west
National protected areas
- Sierra National Forest (part)
- Stanislaus National Forest (part)
- Yosemite National Park (part)