Bon Tempe Lake & Dam – Alpine Lake - Bon Tempe Dam loop from Mount Tamalpais Watershed

If you're ready for a substantial day out on the trails, the Bon Tempe Lake & Dam – Alpine Lake - Bon Tempe Dam loop from Mount Tamalpais Watershed delivers. This difficult hiking route covers 12.0 miles (19.3 km) with a significant 1802 feet (549 metres) of elevation gain, taking approximately 5 hours and 46 minutes to complete. It's a rewarding challenge for hikers seeking panoramic views and diverse terrain around two beautiful reservoirs.

What to expect on Bon Tempe Lake & Dam – Alpine Lake - Bon Tempe Dam loop from Mount Tamalpais Watershed

This loop offers a dynamic journey, transitioning from shaded, woodsy trails reminiscent of the Adirondacks to more open, exposed sections with classic California landscapes. You'll traverse dirt paths and even sandy patches near the lake, with some sections featuring steep but short ascents and descents that demand sure-footedness. The highlight is undoubtedly the impressive panoramic views of both Bon Tempe Lake and Alpine Lake, often framed by the majestic Mount Tamalpais. Crossing the wide, flat Bon Tempe Dam provides excellent vantage points, allowing you to appreciate the scale of these vital reservoirs. Expect to encounter a rich variety of plant life, from redwoods and Douglas firs to valley oaks and madrones, and keep an eye out for abundant wildlife, including various bird species like ospreys and even occasional bald eagles. This route is best suited for well-prepared hikers with good fitness looking for a challenging, full-day excursion.

Planning your visit

The lakes are part of the Marin Municipal Water District's reservoir system, so swimming, boating, and direct water contact are generally prohibited to protect the drinking water supply. A parking fee is typically required at the Sky Oaks Headquarters entrance, so be prepared for that. The trails are generally well-maintained, and many are dog-friendly, making it a great option if you're bringing a canine companion. For the best experience and to avoid potential crowds, consider visiting during the spring or fall when temperatures are milder and wildflowers might be in bloom.

Trail details

• Distance: 12.0 miles (19.3 km)
• Elevation gain: 1802 feet (549 metres)
• Difficulty: difficult
• Estimated time: 5 hours and 46 minutes