Mariposa Creek, originally called the Mariposa River, is a creek that has its source in Mariposa County, California. It flows through the town of Mariposa then southwest through the Sierra foothills, into and across the San Joaquin Valley in Merced County, and empties the sloughs of the San Joaquin River south of the city of Merced.

Mariposa County is a county located in the U.S. state of California. As of the 2020 U.S. Census, the population was 17,131. The county seat is Mariposa. It is located in the western foothills of the Sierra Nevada mountains, north of Fresno, east of Merced, and southeast of Stockton.