Most people at the Tom’s Thumb Trailhead with a rope on their back know the routes. Fewer know the rules, and almost nobody knows that the City of Scottsdale keeps a numbered list of the only places in the Preserve where you can climb at all. This is not a route guide. It’s the legal and historical frame around one: which crags are on the list, what the city lets you do on them, how you’re supposed to walk in, and where the names on the federal map came from.
Climbing is legal here, on purpose
The Preserve’s governing ordinance, Chapter 21 of the Scottsdale Revised Code, names rock climbing alongside hiking, mountain biking and horseback riding as one of the “passive outdoor recreation” uses the Preserve exists to provide. The ordinance itself (No. 3321) was approved by the City Council on May 23, 2000. The details came later, in the city’s Conceptual Rock Climbing Plan: approved by the McDowell Sonoran Preserve Commission in February 2011 and by the City Council in October 2011, with a map of the Tom’s Thumb area dated March 2011 and a second map of the Granite Mountain area dated May 2015. The current guidelines are posted by the McDowell Sonoran Conservancy as a five-page PDF, and the city’s 2024 Ecological Resource Plan still lists the climbing plan as one of the Preserve’s standing management plans.
The plan’s central idea is simple. Climbers were on this granite long before the city bought it, so the city grandfathered the “existing and historical crags” and drew a line around them. Everything else is off limits.
The list
The guidelines name 36 climbing areas, each “and vicinity,” meaning the named rock plus the formations around it. The list “may be modified from time to time” as the city buys land with historical climbing on it.
Tom’s Thumb area (1–18): Rock Knob; Sven Slab; Sven Towers I, II and III; Morrell’s Parking Lot; Morrell’s Wall; Gardener’s Wall; Crossroad Wall; Glass Dome; Goat Hill; Tom’s Thumb; Lost Wall; Half and Half Wall; Fort McDowell Wall; Granite Ballroom; Rosetta Stone; Hog Heaven; Thrasher; Lost in the Air.
Granite Mountain area (19–36): Mogul Wall; The Roost; Sleeping Cactus Wall; Harp Wall; Fairweather Wall; Roofer Madness; Torrid Wall; Trundling Pinnacle; The Loaf; Bobcat Boulder; Riven Wall; The Cone; Lost Bandana Wall; J-Wall; Dueling Hammers; Pasta Pinnacle; Good, Bad, and Ugly Pinnacle; The Den.
The 2011 Tom’s Thumb map also labels two formations that aren’t numbered, Tumbling Dice and The Rist, which sit among the listed areas. Mountain Project, the user-built route database, counted 261 climbs under its McDowell Mountains heading as of this writing (fall 2026). The database is useful. It is not the city’s list, and the list is what a ranger will go by.
The rules, in plain English
The guidelines are short, and every one of them matters:
- Designated areas only, during Preserve hours. That means sunrise to sunset, the same as everyone else. No headlamp sends.
- Walk in on the signed climbing access routes. The Preserve’s general rule is that every user stays on designated trails. The access routes are the exception that connects the main trails to the crags, and they’re the only exception.
- No new routes. None. The city doesn’t create or maintain routes and doesn’t certify grades.
- Fixed anchors stay where they are. Anchor locations are limited to those already established unless city staff authorize otherwise. Replacing old bolts is the climbing community’s job, done by volunteers with their own hardware: old anchors are removed entirely and carried out, old holes are re-drilled and reused where possible, and abandoned holes are sealed with epoxy mixed with rock dust. City staff “will have no role in anchor placements” and make no promises about any anchor’s condition, or that it’s still there.
- Closures happen. Individual routes or whole areas can be closed, temporarily or permanently, to protect natural resources or for safety. The city’s ecological plan includes raptor-nest surveys, which is the kind of finding that closes a wall. Check before you go.
- Bouldering is allowed inside the climbing areas. The guidelines define it as climbing on faces usually under 20 feet. Unroped climbing on the larger formations is “not recommended.”
Violations are prosecuted under Chapter 21, the same code that covers off-trail travel and removing rocks. Everything else in the Preserve rulebook applies too: dogs on a six-foot leash, no drones, no glass, no fires. The trailhead warning signs say it bluntly: climbing “may result in injury or death,” and route selection and the decision to trust an anchor are yours.
Getting there: two trailheads
Crags 1–18 are reached from the Tom’s Thumb Trailhead at 23015 N. 128th Street, via the Tom’s Thumb, Mesquite Canyon, East End and Marcus Landslide trails and the dotted access routes that branch off them. The rock here is the north end of the range, at the foot of East End, the McDowells’ high point. One exception: the city’s map marks Rock Knob as “accessed via County Park,” meaning McDowell Mountain Regional Park next door, which has its own gate and its own entry fee.
Crags 19–36 are on Granite Mountain, reached from the Granite Mountain Trailhead at 31402 N. 136th Street, via the Granite Mountain Loop. The 2015 map is candid that this half of the plan is less finished: it’s labeled “for planning purposes only” and “not intended as a navigational aid,” and two patches of the mountain carry the note that potential access routes “will be evaluated in the field.” The Den is the closest wall to the lot, and Mogul Wall the farthest, on the north end of the mountain.
Neither trailhead has drinking water. The city map is explicit about Granite Mountain, and it asks you not to park on 136th Street.
The rock
Mountain Project describes it as “rough grained desert granite,” with traditional climbing on both gear and bolted lines, and warns that you should expect to place your own protection on a lot of routes. The Arizona Geological Survey’s work puts the granite at the north end of the McDowells, from Tom’s Thumb out across the piedmont toward Cave Creek, at about 1.42 billion years old and thought to be the same granite as Pinnacle Peak. Our geology field guide explains why it weathers into those rounded towers and gravelly slopes.
Pinnacle Peak Park is a separate city park with separate climbing rules. None of the above applies there.
Where the names came from
In 2008 the U.S. Board on Geographic Names made a batch of decisions for features in the Preserve, and three of them are climbing walls. The federal gazetteer (GNIS) records:
- Gardeners Wall (decided June 12, 2008), “just W of the East End.” The history field reads: “Originally named in honor of Ray Garner, longtime area rock climber.” The federal spelling has no apostrophe, and the record doesn’t explain how Garner became Gardener.
- Sven Slab (June 12, 2008), “at the NE end of East End,” about 0.7 mile southwest of Rock Knob. “Named for the Sven power saws used to cut a trail to the base of the wall.” So Sven was a tool, not a climber. The record doesn’t say who ran the saws, or when.
- Morrells Wall (June 12, 2008), “at the N end of East End.” No history recorded. Who Morrell was, the federal file doesn’t say.
The same batch made Bell Pass, Windgate Pass, Horseshoe Ridge and Mesquite Canyon official on June 12, 2008, and Drinkwater Peak and Ochoa Wash on May 8.
Tom’s Thumb is missing from the federal list entirely, and for a good reason. The Conservancy’s “Myths and Mysteries of the McDowells” (Len Marcisz, Fall 2020) gives the spire’s elevation as 3,925 feet and its first ascent as September 19, 1964, by local mountaineer Tom Kreuser, and notes that the formation can’t be officially named for him because the Board on Geographic Names does not honor living persons. So the best-known rock in Scottsdale is, on paper, unnamed.
The standard local reference for routes is McDowell Rock: A Climber’s Guide by Erik Filsinger and Cheryl Beaver (2016). For the older names, the answer probably lives in Stewart Green and Jim Waugh’s 1987 Phoenix Rock, which predates the Preserve and the federal decisions. If you own a copy and know who Morrell was, we’d like to hear from you.
What we don’t know yet
The fight that produced this plan, the years when climbers reached the north McDowells through Troon and the city was still buying the land, is told on our Tom’s Thumb page from the trailhead side. The climbers’ side belongs to the Arizona Mountaineering Club, which still hosts a copy of the 2011 plan, and to the people who sat through the Preserve Commission meetings in 2010 and 2011. Those minutes, held by the city, would show who asked for what.
The short version
Check the list, walk in on the signed access route, leave the bolts alone unless you’re the volunteer replacing them, and don’t drill anything new. For current closures, the Preserve office number printed on the city trail map is 480-312-7013. Call before a trip to the Granite Mountain walls in particular, where the plan itself says the access routes were still being worked out. And if the wall you want isn’t on the list, it isn’t legal, however many stars it has online.