Garwood Dam and Wildhorse Tank Loop

Garwood Dam and Wildhorse Tank is a 6.4-mile loop from Douglas Spring Trailhead, combining Douglas Spring, Garwood, Carrillo and a steep side trip on Wildhorse to Little Wildhorse Tank. The listed mileage includes going out to the tank and returning to Carrillo; it is not a separate hike to add after the loop. Allow four to five hours for the rocky footing, climbing and stops. This is a rewarding half-day walk if you want more than a short cactus-forest stroll: it links an old ranch dam, a winding foothill ridge and one of the park's few perennial-water areas.

Start at Douglas Spring Trailhead at the east end of Speedway Boulevard. Follow Douglas Spring about 0.2 mile and turn right onto Garwood. At the dam, stay on Carrillo; take the Wildhorse spur to Little Wildhorse Tank, retrace it, then continue on Carrillo to the steel tank and wash. The return follows Carrillo to Douglas Spring and back to the trailhead. Several trails meet here, so keep track of the names and turns rather than following the most obvious tread. The way back from the wash can be easy to miss.

Garwood begins among tall saguaros, mesquite, palo verde, creosote, ocotillo, brittlebush and cholla. The tread is relatively level for much of this stretch, with a short sharper rise near the Wildhorse and Bajada Vista junctions. Follow Garwood toward Carrillo rather than turning onto either neighboring route. Near the dam the walk becomes steeper, and the broad cactus forest gives way to canyon and rocky foothill terrain.

Nelson and Josephine Garwood bought 450 acres here in 1945. Nelson began building the dam and the first ranch house in 1948 to hold water for the family place; two large storage tanks were part of the setup. The family left in 1959, and later fire and vandalism took most of the buildings. The dam is the most substantial ranch structure still standing. Look at it from the trail and do not climb it; the structure is unsafe. The old masonry against the desert basin is the route's strongest photo scene, with cactus-covered slopes beyond it.

From the dam, Carrillo crosses rugged ground and climbs a series of switchbacks. Views open on the foothill ridge, first west toward Tucson and the Tucson Mountains, then across the Rincon and Santa Catalina ranges as the trail turns. At the Wildhorse junction, make the steep side trip to Little Wildhorse Tank and return to Carrillo. The tank is a rare perennial-water feature, not a confirmed place to refill bottles. Expect the ridge and lower desert sections to be exposed; there is no food or potable water listed for the route, so bring what you need from the start.

After the tank, continue on Carrillo past a rusted steel tank in a small wash. Look for the trail as it leaves the wash, then turn onto Douglas Spring for the final descent to the same trailhead. The intersections near Bajada Vista and Wildhorse can be confusing, and the Carrillo sign at the dam is easy to overlook. Give yourself time to check each junction. Park rules prohibit dogs on this route, with service animals exempt. Walk-in visitors age 16 and older need the individual park entrance fee unless covered by a pass.

Watch the saguaro trunks for nesting cavities: Gila woodpeckers and gilded flickers use them. The tank and dam are the obvious stops, but this is also a good loop for seeing how the cactus forest thins into the rocky foothills and opens to long views over Tucson.