April 2001

Type: Community Open Space and SNRA park, 122 acres.
Access Points: The best entrance point is off Diamond Heights Blvd. Park in the Diamond Heights shopping center parking lot just north of Goldmine St. Behind the shopping center is the George Christopher Playground with a baseball field. A trail circles the field and from it there is a path into Glen Canyon. Less recommended is the Bosworth St entrance where Bosworth breaks north off O'Shaugnessy as a small residential street. This is at the lowest point in the park where eucalyptus trees dominate. Parking difficult. These are the only two access points discovered.
Facilities: Inside Glen Canyon: Co-operative community pre-school, nothing else. George Christopher Playground: Glen Canyon Recreation Center, playground, water, restrooms are lockout, softball field, 1 tennis court, basketball. Diamond Heights Shopping Center adjacent with phone. Bosworth side: Rec field (school related), 2 tennis courts.
Fee-Hours: No fee. No curfew noted.
Dogs: Poor for dog use. Poison oak, sensitive preserve area, no open running spaces, steep and narrow gravelly trails.

Glen Canyon, established as a park in 1922, is a sizeable area of preserved ravine which descends from Twin Peaks as part of the Twin Peaks, Mt. Sutro mountain complex. Not only is it one of the larger parks of San Francisco at 122 acres, it is perhaps the finest example of a natural habitat for an inland area (inside San Francisco). It shares this distinction with Twin Peaks with which it is almost contiguous. Twin Peaks, however, is only really accessible at the top where it is crowded. Glen Canyon (also Glen Park) is not crowded and has ample trails throughout its prettiest part, which is midsection along its open slopes. Although numerous parks are considered Significant Natural Resource Areas (SNRA) in San Francisco, Glen Canyon is especially relevant in that regard as an inland preserve of significant size. Although eucalyptus has a foothold on the southern part of the park, the park is not dominated by eucalyptus like Mt. Sutro or Mt. Davidson. Evidence of park development is minimal and is appropriately focussed on protecting the natural creek watershed that runs down this ravine. The word inland is stressed for Glen Park because it can hardly be argued that the most significant natural resource areas remaining in San Francisco are coastal, specifically in the Lands End area, Fort Funston area, Presidio Cliffs, and Lake Merced. Inland, however, it is Glen Canyon and Twin Peaks which rule, followed by McLaren Park, and various hilltop parks. Glen Canyon is characterized by large areas of grasses and wildflowers on open hillsides facing west, impressive masses of rock formations, and a stream which supports a dense margin of willow trees. An interesting contribution to the park comes in the form of mosquito abatement and involves the introduction of bats through the installation of nine 'bat houses.' The lowest, southern part of the park is dominated by eucalyptus and is less interesting. These trees were originally planted for wind abatement by Adolph Sutro in the 1850s when he owned the land, subsequently naming it 'Gum Tree Ranch.' The eastern facing slopes are covered by a very dense mat of soft chaparral. This amounts to zero access from upper O'Shaugnessy. Although impenetrable to people, this chaparral area no doubt serves as a welcome haven for various small wildlife. The accessible portion of the park is so beautiful in spring that it is like being transported magically out of the city and into wild hills of Sonoma or Marin County. That is the most distinctive quality of this park. It is a natural landscape which appears as though it's hardly been  touched, which is in fact not the case at all. This canyon has gone through many metamorphoses of development.* The 'nature area' of the creek explodes seasonally with verdancy: horsetails, rushes, and many other things. It is one of the most beautiful natural oasis in the city in spring season. The park loses much when spring fades to summer.

One aspect which keeps the crowds down is that good access is hard to find, a fact which serves the park well. Bosworth off O'Shaugnessy is the 'main' entrance but it begins bogged in eucalyptus and street parking is difficult. There is only one other access point discovered and though almost completely hidden, is excellent. It is a dramatic, sudden revelation of the park interior from high up which is simply stunning. It occurs midsection of the park behind Diamond Heights Shopping Center and George Christopher Playground. An offshoot path enters from a trail which circles the baseball green to suddenly reveal the canyon. Recreational facilities exist in parks and school grounds around the periphery, but inside Glen Canyon there are no facilities, including no tables. A special feature often attributed to Glen Park is rock climbing. There are two main concentrations of rock formations. Bouldering faces can reach up to 30.' These two formation areas also happen to be natural magnets as places to sit and enjoy the area, or to bring some food and spread out. Lizards live here amidst the rocks, uncommon for San Francisco. Poison Oak has an annoying foothold and it is necessary to be careful of poison oak here. It is also one of many reasons why it is not a good place to unleash a dog.

As such a fine preserve, especially in combination with the creek nature margin, Glen Canyon is considered the third finest park overall in San Francisco.

Best Features: Unusual and attractive preserve area with open ravine hills and interesting rock formations. Safe and uncrowded. Natural habitat for this area.

Worst Features: The lower (southern) section is less appealing and has poor parking. Get ready for steep, gravelly trails. Poison oak is avoidable but abundantly present in the nicest places.

* For more on the 'colorful' history of Glen Canyon, read an informative essay by Jeanne Alexander at

Also, there is The Glen Park Association:
P.O. Box 31292
San Francisco, CA 94131
Tel: (415) 908-6728

Glen Canyon Park:
contact: 415.337.4705


Hillside inside Glen Canyon