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A lesser known loop in the Tucson Mountains with great flow and fun climbs.

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2,883' 879 m


2,520' 768 m


1,001' 305 m


1,001' 305 m



Avg Grade (1°)


Max Grade (7°)

Dogs Unknown

E-Bikes Unknown

Dogs prohibited, but I see them on the trail all the time.


The Robles trail network connects to the Tucson Mountain Park trails through two culverts under Ajo road. Adding on a loop in the Robles system adds more distance, variety, flow, and in my opinion fun to the "standard" loops in Tucson Mountain Park. This loop is by no means the only way to ride Robles, but it is in my opinion the best tour of all it has to offer. Once you learn how to navigate these trails, and get a feel for the various connectors, you'll realize just how much variety TMP and Robles provide.

This ride starts at the Genser trailhead, near the Starr Pass Marriott. The first mile and a half are the same as the Starr Pass Main Loop. After taking a left at one of TMP's three-way intersections, you'll navigate a series of flowing trails with fun obstacles to progress south towards Ajo road. Once you cross under Ajo via the culvert you'll be rewarded with fast, flowy, occasionally rocky singletrack. Most of the Robles loop is of intermediate difficulty, but the climb on Bittersweet trail will challenge even the most experienced riders.

Need to Know

This route has been revised to follow the updated TMP trail map (…), using the Portal Trail to access the easternmost end of Explorer Trail.

Use the tunnels below Ajo Road to cross from TMP into the Robles system rather than crossing the busy and dangerous road.


Start by heading west into the Tucson Mountains on the Rock Wren Trail. Hang a left at the Starr Pass four way junction as if you were riding the Starr Pass Main Loop clockwise. Take a left at the next two three-way junctions to head towards Robles on the Starr Pass Trail and the 36th Street Trail. This section is fast and fun and perhaps the smoothest that TMP has to offer.

At the third three-way junction go right, heading to the SSE on the 36th Street Trail. From here the trail becomes a bit rocky and you'll cross in and out of washes. Follow the tire tracks to make sure you come out on singletrack on the other side. At the next three-way junction you encounter, go right to head south again on an unnamed connector trail. If you were to go left at this intersection you would continue on the 36th Street Trail and eventually reach the 36th St. Trailhead, which is an option if you'd like to keep the ride under 10 mi and still reach Robles.

In a few hundred meters the trail spits you out on a paved road in a neighborhood. Progress south on said road (Mockingbird Ln) until you see a two track heading almost directly south, up a hill, branching from the road. At the top of this short hill this unnamed trail becomes singletrack once more. There is usually a "no hunting" sign posted here. See the photos for a picture of this location.

Once you've crested the hill starting with the "no hunting" sign, which is no small feat, bear left at the three way junction and you'll be rewarded with a fun, fast descent. You'll cross a two-track road before you reach the Ajo culverts. The first culvert you'll cross under can be accessed by descending a short ways into the wash from the small parking area on the roadside. See photos for a shot of this 4' culvert. It's rideable, even for a tall person like me, but be careful of debris in the darkness. Lest you think that this culvert crossing cannot be the official trail, a very official looking trail map is posted on the immediate south side of Ajo road, at the exit of the culvert. Since the Robles trails are so well marked, detailed turn instructions are not included here in favor of a general trail to trail to trail approach.

Once you are in the Robles system, you'll ascend a fast, flowing switchback climb away from Ajo Road. Make a clockwise loop around the system on Ledge Surfer, the east side of Camaro Loop, then Bittersweet Trail. The hill on Bittersweet is an excellent technical and fitness challenge, but can be skipped using the west side of the Camaro Loop connected to the Sunset Pass Trail. Bittersweet terminates at the Sunset Pass Trail just before it ends at the second culvert (6' this time).

Cross under the second culvert and proceed north on Explorer Trail until you reach another three-way junction. Take a right to stay on the Explorer Trail (the left side sends you over a technical climb on the Cat Mountain Trail). At the next junction you'll take a left to retrace your steps back towards the 36th Street Trail on the unnamed connector. To finish off this ride, take a right at the three-way junction and head east on the Starr Pass Trail, towards the Starr Pass golf course.

Take a left at the intersection soon after you cross through a gated (always open) fence, before you start descending, to connect to the Rock Wren Trail. This connector ascends the infamous "F*&$ You Hill". If you have ridden this hill before you'll understand the name. Pro tip: stay left when you attempt this steep, loose, two-pitched climb. Once you reach the top, turn right on Rock Wren Trail to end at the Genser Trailhead.


Shared By:

Drew Laskowski

Trail Ratings

  4.1 from 18 votes


  4.1 from 18 votes
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in Arizona


133 Views Last Month
10,594 Since Aug 16, 2014
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Figuring out which route to take.
Feb 10, 2018 near Tucson…, AZ
The crest of the hill on Bittersweet Trail rewards with amazing views to the east and west. This photo is looking west towards the fast, fun descent that is your reward for making the climb.
Sep 11, 2014 near Drexel…, AZ
The infamous finishing climb on Robles Loop from Genser Trailhead. Stay left, trust me.
Sep 11, 2014 near Tucson…, AZ
Riding here, it is easy to forget you are so close to the city, except for the rare hilltops you can see it from.
Jan 13, 2017 near Drexel…, AZ
Down the final switchback
Dec 20, 2014 near Drexel…, AZ
Final rock
Dec 20, 2014 near Drexel…, AZ


Current Trail Conditions

All Clear 50 days ago
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