The 450,000 acre (1,800 km²) "zone" in which the conservancy can acquire land is bounded on the south by the Pacific Coast Highway from Santa Monica to Point Mugu. The zone extends inland roughly 50 miles (80 km) from Malibu north to Newhall Pass and 65 miles (105 km) from Thousand Oaks east to Pasadena. Several major freeways in Los Angeles cross the zone, including the Hollywood, Ventura, San Diego and Interstate 5.
Since its founding, the Conservancy has acquired 21,000 acres (85 km²) and identified another 15,000 acres (61 km²) within its zone as crucial for preservation. In addition to buying land outright, the Conservancy operates through public-private partnerships to promote low-density use among private land-owners. The conservancy also acquires rights to land through "time-leasing", receives land through donations and acquisition of foreclosures, and as mitigation for development projects.
The Conservancy zone includes the 155,000 acre (627 km²) Santa Monica Mountains National Recreation Area, created by Congress in 1978, as well as 40,000 acres (162 km²) of state parks, including Topanga State Park and the Marvin Braude Mulholland Gateway Park, which are within Los Angeles' city limits.
The Conservancy was responsible for the acquisition of the Jordan Ranch in the Simi Hills from entertainer Bob Hope. The ranch was purchased by a developer and turned over the National Park Service as part of a land development deal, which allowed development of new housing and golf course on the Ahmanson Ranch just to the west. Late in 2003, the Conservancy secured state funds to purchase Ahmanson Ranch as well.