Mount Tamalpais Watershed
Bon Tempe Lake
Neil Wiley

After gorging on my granddaughters’ food (Emme’s pies and Morgan’s potato boats) during the holidays, I needed walking, so my daughter April and two dogs led me around one of Marin County’s many lakes. A hike circling Bon Tempe Lake proved to be the perfect choice.

After driving along many twists and turns, we turned right on Bon Tempe Dam Road to a parking area on the left. A short walk up a mild grade took us to the Sunnyside Trail. From there, we could see down the length of Bon Tempe Lake, across the dam in the foreground, and to Alpine Lake in the distance.

Although it was late December, the weather was perfect for walking—a cool sixty degrees and sunny. To make it even better, we stayed warm by turning left at the lake to take the well-named Sunnyside Trail. (On a July day, you might prefer crossing over the dam to Shadyside Trail on the other side of the lake loop.) The Sunnyside Trail also provided consistent unimpaired views across the width and length of the watershed’s widest lake and the imposing Mount Tamalpais.

The single-track trail was relatively flat with only a few muddy spots after a rain, good for walkers but closed to cyclists. (The nearby Lake Lagunitas Road is popular with two-wheelers.)

On the other hand, dogs on leash and dog-walkers are welcome on the single-track Bon Tempe trails. This encourages social interaction as dog-walkers tell you that “My dog doesn’t bite” or “You can pet him.” This is followed by friendly expressions of dog love, unless the statements prove wrong. (Our dogs didn’t bite, and they could be petted.)

This is a popular destination close to the residential communities of Fairfax and San Anselmo. While you are in a natural environment, you can enjoy relative safety. It is almost impossible to get lost. You can see and be seen from almost anywhere on the trail. The trail around the lake is 4.1 miles. Out and back on the Sunnyside trail is two miles.

If, however, you want more adventure or solitude, you can follow trails throughout the Mount Tamalpais watershed. Just be sure to have a map. The watershed covers 19,000 acres with 138 miles of trails and unpaved roads.

You have many choices. For example, from the Bon Tempe Lake trailhead, you can walk across the dam to reach the Alpine-Bon Tempe Road and Kent Trail along the shores of Alpine Lake. Other trails can take you to Lake Lagunitas and the popular Phoenix Lake. (To learn more about Phoenix Lake, click on hikes at

Traveling to Marin County from our mountains in non-commute times usually takes an hour and a half. If you are looking for new explorations, it’s worth the trip, especially if you have a free weekend, or better yet, free lodging. Enjoy.

Directions. Highway 17 north, 85 north, 280 north, 19th Avenue/Golden Gate Bridge, 101 north, exit 450B toward San Anselmo, merge to Sir Francis Drake, left on Pacheco Ave., right on Broadway, left on Bolinas Road, left to stay on Bolinas Road, slight left on Sky Oaks Road, right on Bon Tempe Road, slight left on Rocky Ridge Road, and right on Bon Tempe Dam Road. Parking is on the left. For your GPS, use the location Bon Tempe Dam Road. If the