Rancho Jurupa was a 40,569-acre (164.18 km2) Mexican land grant in California, United States, that is divided by the present-day counties of Riverside and San Bernardino. The land was granted to Juan Bandini by Governor Juan B. Alvarado in 1838. Located along both banks of the Santa Ana River in southern California, the rancho included much of the land in the present day city of Jurupa Valley, as well as the downtown area in the city of Riverside.

Riverside County is a county located in the southern portion of the U.S. state of California. As of the 2020 census, the population was 2,418,185, making it the fourth-most populous county in California and the 10th-most populous in the United States. The name was derived from the city of Riverside, which is the county seat.