The park covers 2,352 acres (9.52 km2) in the Black Mountain Ranch and Rancho Peñasquitos area of northern San Diego.

[1] The park offers numerous trails for hiking and biking, and boasts a variety of native animal and plant species.

Native plant species preserved in Black Mountain Open Space Park include both chaparral and coastal sage scrub.

[6] Tucked away in the Black Mountain canyon is an abandoned arsenic mine, accessible via pathways branching off of the park's Miner's Ridge Loop trail.

The mine was established in the 1920s by Escondido rancher, rodeo cowboy, and actor Frank Hopkins, due to the demand for white arsenic, a key ingredient in pesticides that attacked infesting boll weevils.