Santa Monica Mountains NRA contains 154,095 acres (623.6 km²), California State Parks own 42,000 acres (170 km²), the National Park Service controls 21,500 acres (87 km²), and the rest are local park lands and private property. In size, Santa Monica Mountains NRA is the largest urban national park in the United States. The park was established November 10, 1978, after a campaign for the area by local conservationists. The park is intended as an extension of Channel Islands National Park, which is just the underwater portion of the Santa Monica Mountains immediately to the west.
The following California State Parks are located within Santa Monica Mountains NRA:
Entertainer Bob Hope caused controversy in the early 1990s when he proposed to sell 5,900 acres (23.9 km²) of neighboring land to the federal government in exchange for 59 acres (0.24 km²) of federal parkland in the nearby Cheseboro Canyon section of Santa Monica Mountains NRA in order to build an access road serving a new golf course and housing development. The land swap was never completed.