Glen Canyon Park
Glen Canyon Park is a city park in San Francisco, California. It occupies about 70 acres (28 ha) along a deep canyon adjacent to the Glen Park, Diamond Heights, and Miraloma Park neighborhoods. O’Shaughnessy Hollow is a rugged, undeveloped 3.6 acres (1.5 ha) tract of parkland that lies immediately to the west, and may be considered as an extension of Glen Canyon Park.
The park and hollow offer an experience of San Francisco's diverse terrains as they appeared before the intense development of the region in the late 19th and the 20th centuries. The park incorporates free-flowing Islais Creek and the associated riparian habitat, an extensive grassland with adjoining trees that supports breeding pairs of red-tailed hawks and great horned owls, striking rock outcrops, and arid patches covered by "coastal scrub" plant communities. In all, about 63 acres (25 ha) of the park and hollow are designated as undeveloped Natural Area. Elevations in Glen Canyon Park range from approximately 225 feet (69 m) above sea level at the south end of the park to 575 feet (175 m) above sea level at the north end and along the east rim of the canyon; the walls of the canyon are extremely steep, with many slopes approaching a length-to-height ratio of 1:1 (100 percent).