Anza-Borrego Desert State Park is a state park located within the Colorado Desert of Southern California. The park takes its name from 18th century, Spanish explorer Juan Bautista de Anza and borrego, the Spanish word for bighorn sheep. With 600,000 acres (2,400 km2) that include one-fifth of San Diego County, Anza-Borrego is the largest state park in California and, after New York's Adirondack Park, the second largest in the continental United States. The park occupies eastern San Diego County and reaches into Imperial and Riverside Counties.