McKennan Gulch Trail to Bolinas Lagoon - 3.9 Miles Round-Trip

The McKennan Gulch Trail is a short but physically and navigationally challenging route from Ridgecrest Blvd to Bolinas Lagoon. Bolinas Lagoon is a small, shallow estuary separated from the Pacific Ocean by Stinson Beach, a long spit which ends at the lagoon's mouth.

Trail Map | Photo Gallery

Estuaries are semi-enclosed coastal bodies of water with fresh water influx and a free connection to the open sea. Contributions from each make estuaries one of the most biologically diverse ecosystems on earth.

Bolinas Lagoon covers 3,500 acres directly over the San Andreas Fault. It's 3.45 miles long and 1 mile across at its widest point. The lagoon supports several micro-habitats, including subtidal channels, eelgrass beds, rocky and mudflat intertidal substrates, salt marsh, and upland marsh.

Harbor seals, osprey, egret, heron, pelican, fox, migratory birds and many small fish depend on this delicate matrix for food and shelter. Bolinas Lagoon is one of just nine places in the San Francisco Bay Area used by harbor seals year-round.

Though neatly depicted on maps, the McKennan Gulch Trail is unmaintained and difficult to follow at times. Anticipate thick chaparral and poison oak. Prepared hikers will enjoy exceptional views, varied terrain, certain solitude and diverse wildlife:

The McKennan Gulch Trail leads out to an unmarked 4-way split (.1 mile). To the far right is a spur leading to a bench and overlook; the faint dirt path to its left is the correct trail. The two remaining choices climb a knoll, which should help you rule them out.

The correct path drops steeply on dirt, the remains of a dairy ranch road that offers a measure of guidance on the descent. The trail wraps around an outcrop and levels into a cluttered forest (.35 miles : 1,500'), where you'll be led by an old fence to the right.

The trail emerges from timber (.5 miles : 1,445') in a grassy slope with coastal views from Palomarin (north) to San Francisco Bay (south). On clear days the Farallon Islands can be seen 26 miles out. Purple iris, yellow poppies and the ceanothus shrub - known for its bright blue tufts - dot the grasslands. 

Survey the land, identify faint tracks in the grass and locate upper Stinson Gulch to the south before continuing. The trail dives down the open slope, edging away from Stinson Gulch and shifting quickly through an odd mix of coastal chaparral and diminutive pine. Patience is key through this ill-defined space.

Grade moderate (1.25 miles) through dense manzanita to a Hiker signpost pointing left (1.35 miles : 432'). Travel eases briefly on a more distinct path that leads into a doug-fir forest at the top of Stinson Gulch. The trail arcs over the gulch and opens up again on the side (1.7 miles : 210').

It pitches steeply down once more to the McKennan Gulch Trailhead off of Highway 1 (1.95 miles : 30'). The trail ends in the driveway of an old barn just off highway. An adjacent, uncommonly large cactus patch will draw your attention. Bear right in the driveway and follow it to Highway 1 and Bolinas Lagoon (2.25 miles).