Simmons - Mickey O'Brien - Cataract Trail Loop, Mt Tamalpais State Park - Rock Spring Trailhead, San Francisco: Marin Headlands - Mt Tamalpais - Point Reyes, California

Simmons - Mickey O'Brien - Cataract Trail Loop - 2.95 miles

Mt Tamalpais State Park - Rock Spring Trailhead

A lizard rests on a serpentine outcrop along the Simmons Trail

A lizard rests on a serpentine outcrop along the Simmons Trail

Round-Trip Length: 2.95 miles
Start-End Elevation: 1.965' - 1.965' (2,223' max elevation)
Elevation Change: +258' net elevation gain (+573' total roundtrip elevation gain)
Skill Level: Easy-Moderate
Dogs Allowed: Yes
Bikes Allowed: No
Horses Allowed: No
Related Trails:

Simmons - Mickey O'Brien - Cataract Trail Loop - 2.95 Miles Round-Trip

The Simmons, Mickey O'Brien, and Cataract trails form a short but varied loop through open meadows, deep woodlands and rocky outcrops from the Rock Spring Trailhead. This ecologically diverse route is ideal for families or a short trail run, and those with time can explore the picnic area, sunny slopes and natural spring at Barth's Retreat. The following description travels counter-clockwise on the loop:

Trail Map | Photo Gallery

Head north on the Cataract Trail to the Benstein Trail (.07 miles) and veer right. The Benstein Trail rises gently to the Simmons Trail (.17 miles : 1,948'), on which you'll turn left through mixed forest and slender glades to a creek (.33 miles : 1,984').

Once across grades steepen into a markedly drier area called a serpentine outcrop (.43 miles : 2,071'). Serpentine outcrops are characterized by the eponymous rock, swaths of manzanita, chaparral pea, chaparral oak and sargent cyprus stands.

Heavy metals in serpentine rock such as iron, nickel and magnesium limit plant communities to only the most tolerant and adaptable. Fittingly, this is a good place to find lizards and snakes. 

The trail is occasionally faint but intuitively followed to its crest (.6 miles : 2,221') with good northerly views across interior highlands. It drops on a shifting, rugged path back into Douglas-fir forest at the Simmons Trail - Mickey O'Brien Trail junction at Barth's Retreat (1.0 miles : 1,962').

A spur branches off into Barth's Retreat's sloping meadows and outcrops, a worthwhile diversion, especially when in bloom.

Turn left on the Mickey O'Brien Trail, which undulates along Barth's Creek to the Cataract Trail junction. (1.75 miles : 1,708'). The Cataract Trail bends south and moderates along the Cataract Creek. It rises gently to the edge of a long meadow (2.25 miles : 1,850'), re-enters the woods and emerges again in the broad expanse of Rock Spring.

The Cataract Trail glides through the meadow back to Rock Spring Trailhead to complete the loop (2.95 miles : 1,965').

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Interactive GPS Topo Map

Key GPS Coordinates - DATUM WGS84

  • N37 54.654 W122 36.766 — 0.0 miles : Rock Spring Trailhead
  • N37 54.706 W122 36.803 — .05 miles : Cataract Trail - Benstein Trail split
  • N37 54.756 W122 36.864 — .33 miles : Benstein Trail - Simmons Trail split
  • N37 55.088 W122 36.894 — .6 miles : Highest point of loop on Simmons Trail
  • N37 55.350 W122 37.002 — 1.0 miles : Simmons Trail - Mickey O'Brien Trail split
  • N37 55.311 W122 37.570 — 1.75 miles : Mickey O'Brien Trail - Cataract Trail split
  • N37 54.849 W122 37.294 — 2.25 miles : Emerge from forest on edge of meadow
  • N37 54.654 W122 36.766 — 2.95 miles : Rock Spring Trailhead

Worth Noting

  • The natural spring at Barth's Retreat is not potable.

  • Be mindful of snakes in rocky outcrops, and never place your hands or feet where you can't see them.

  • Serpentine Rock is the state rock of California.

Camping and Backpacking Information

Backcountry camping is not permitted within Mt Tamalpais State Park.

Pantoll Campground

  • The Pantoll Campground is located on Panoramic Highway adjacent to the Pantoll Ranger Station. It has 16 campsites, each with a table, rock barbecue, food locker and space for a tent. Phones, faucets, firewood and flush toilets are nearby. There are no showers. Sites are first-come, first-served.

Steep Ravine Environmental Campground

  • The Steep Ravine Environmental Campground is located on a coastal terrace off Highway 1, one mile south of Stinson Beach. It has nine rustic cabins and seven primitive campsites. Each cabin has a wood stove, picnic table, benches, sleeping platforms and outdoor bbq.
  • The cabins do not have running water or electricity. Primitive toilets, faucets, and firewood are nearby. Primitive campsites are located a few hundred yards from the parking area. Each site has a table, fire pit, food locker and space for a tent. Primitive toilets and water faucets are nearby. There are no showers at Steep Ravine Campground.

Alice Eastwood Group Camp

  • Alice Eastwood Group Camp is located off Panoramic Highway on Alice Eastwood Road. It has two campsites. Site A holds up to 50 people; Site B holds up to 25 people. Both sites have tables, flush toilets, water faucets with sinks, bbq grills and a large area for tents.

Frank Valley Group Horse Camp

  • Frank Valley Group Horse Camp is located 1.5 miles West of Muir Woods National Monument on Muir Woods Road. It has 12 pipe corrals, water faucets, watering troughs, picnic tables, fire rings and a pit toilet. The minimum group size is 2 horses; the maximum size is 12 horses.
  • To reserve a campground visit or call 800.444.7275. For specific camping and campground questions, call Pantoll Ranger Station at 415.388.2070.

Rules and Regulations

  • Dogs are permitted but must be leashed at all times.

  • Bikes are not permitted on any portion of the loop trail.

  • Fishing is not permitted on any portion of the loop trail.

Directions to Trailhead

Mt Tamalpais State Park is located north of San Francisco in Marin County. The Rock Spring Trailhead is located 9.9 miles from Highway 101 on Panoramic Highway. The Rock Spring Trailhead is located 1.4 miles north of the Pantoll Ranger Station at the Pantoll Road and West Ridgecrest Blvd intersection.

From Highway 101, exit Stinson Beach – Highway 1 and follow the exit ramp west .6 miles to the Highway 1 – Almonte Blvd intersection. Turn left on Highway 1 toward Stinson Beach.

The road winds up the mountain to the Panoramic Highway split (3.2 miles) – veer right on Panoramic Highway (anticipate this quick turnoff). Remain on Panoramic Highway and follow signs for Mt Tamalpais State Park to the Pantoll Ranger Station (keep straight at the Muir Woods – Mill Valley fork at 4.0 miles). From the Pantoll Ranger Station, veer right up Pantoll Road and continue 1.4 miles to the Rock Spring Trailhead parking area.

Contact Information

Mt Tamalpais State Park
801 Panoramic Highway
Mill Valley, CA 94941

Marin Municipal Water District
220 Nellen Avenue
Corte Madera, CA 94925-1169

Trip Reports

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