Mariposa County is a county in the U.S. state of California, located in the western foothills of the Sierra Nevada mountains. It lies north of Fresno, east of Merced, and southeast of Stockton. As of the 2010 census, the population was 18,251 up from 17,130 at the 2000 census. The county seat is Mariposa.
The county's eastern section is the central portion of Yosemite National Park.
There are no incorporated cities in Mariposa County; however, there are three communities recognized as census-designated places for statistical purposes. It also has the distinction of having no permanent traffic lights anywhere in the county.
Mariposa County was one of the original counties of California, created at the time of statehood in 1850. While it began as the state's largest county, over time territory that was once part of Mariposa was ceded to twelve other counties: Fresno, Inyo, Kern, Kings, Los Angeles, Madera, Merced, Mono, San Benito, San Bernardino, San Luis Obispo, and Tulare. Thus, Mariposa County is known as the "Mother of Counties".
The county took its name from Mariposa Creek, which was so named by Spanish explorers in 1806, when they discovered a great cluster of butterflies ("mariposas" in Spanish and Portuguese) in the foothills of the Sierras. Each year, the first weekend in May, residents mark the annual arrival of migrating Monarch butterflies with a "Butterfly Days" festival and parade.
The Gold Rush
Mariposa County is located at the southern end of California's Mother Lode region. During the California Gold Rush, great quantities of the prized mineral were found and extracted, first in local stream-beds and later in hard rock mines. One of the most notable beneficiaries of this wealth was the famed explorer and 1856 Republican presidential candidate, John C. Frémont, for whom the local hospital is named. (Jessie Street, in the town of Mariposa, is named for Fremont's wife, Jessie Benton Frémont, who came to Mariposa to live with him.)
Many aspects of the area's mining history are depicted in exhibits at two local museums: the Mariposa History Museum, located in the town of Mariposa; and the California Mining and Mineral Museum, located at the Mariposa Fairgrounds (2 miles east of Mariposa on Highway 49).
Two small gold mines in Mariposa county, the Mockingbird and the Colorado Quartz, intermittently produce world-class (and very expensive) 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", now on display at the Houston Museum of Natural Science.