Your Local Crag: Glen Canyon

Glen Canyon is San Francisco’s premier outdoor bouldering destination.  While many guidebooks pan it as being “the only, and therefore ‘best’ bouldering in the city”, the reality is that it is actually a great bouldering spot, offering good climbing on a generally solid, unique type of rock (radiolarian chert).  While most of the obvious lines are “easy” (V1 or less) – albeit highball (up to 30′ tall), the imaginative boulderer willing to look beyond the obvious jugs will find endless hard variants and eliminates.  The crag’s motto could be “between any two holds is another, smaller hold just waiting to be cranked”!

Access:  History and Acceptable Climbing Areas
Thanks to advocacy work by local climbers in the early 1990s, climbing was officially designated in the plan of management at a number of locations in the park.  Notably, climbing is allowed at the main cliff band, and at the buttress containing the classic highball roof problem known as “The Unnatural Act”.
Climbing was also explicitly banned at the outcrop sometimes referred to as “Dead Cat Rocks” or “Deep Canyon Boulder”.  Please avoid this area!  The rock on this outcrop is chossy, it is heavily overgrown with poison oak, and (most importantly) the land manager is protecting the habitat for several delicate species of plants that only grow on the chert outcrops.  There are several other climbable outcrops in the park that are not mentioned in the relevant section (§6.3) of the plan of management, and climbers are requested to avoid climbing on these outcrops until the access situation can be clarified with the San Francisco Recreation & Parks Department.


BACC Work at Glen Canyon
The BACC has held Adopt-A-crag Events in the park every year since 2014, with well over 100 volunteers having worked in the park to build, repair and improve trails, clear brush, collect trash and broken glass, remove graffiti, and more.  In doing so, we have established a good relationship with the San Francisco Recreation & Parks Department and look forward to many more Adopt-A-Crag events in the park.


The Surrounding Area
Glen Canyon Park is a lovely little window into what the San Francisco hills looked like before the city sprawled over them, with a large area of native vegetation, a natural creek (Islais Ck, one of only two open creeks left in the city), and plenty of wildlife (including the famous Glen Park coyote).  The recently completed Creeks to Peaks Trail is a wonderful 2 mile hike from the bottom of the canyon all the way to the top of Twin Peaks – in that distance you will gain around 900′ of elevation.  The eventual plan is to officially link this trail down to Golden Gate Park, via Mt Sutro Open Space Preserve and the Interior Greenbelt, at which point it will be possible to walk from Glen Park BART to Ocean Beach, with only a few short blocks of walking on city streets!


Glen Canyon History
Glen Canyon Park has had a colorful history since the founding of San Francisco.  Originally part of Rancho San Miguel (which covered large swathes of what is now southern and western San Francisco), Adolph Sutro purchased the canyon in the 1850s and renamed it the Gum Tree Ranch.  In 1868 it became the location of the first dynamite factory in the United States, but two years later an explosion leveled the factory and it was relocated out to the sand dunes of the outer lands (what is now the Sunset District).  In 1889 an amusement park was established in the canyon, which included a small zoo, hot air balloon rides, and tightropes strung across the canyon.  In 1922 the city purchased the land, and the canyon became an official public park.  A 1958 plan to widen & straighten O’Shaughnessy Blvd as part of a proposed crosstown freeway caused one of the earliest skirmishes in the so-called freeway revolts – the multi-lane lower section of Bosworth St (down near Glen Park BART station) is a relic of the early phases of this work.