Sir Francis Drake Bikeway, also known as the Cross Marin Trail, is a rail-trail built on the old North Pacific Coast Railroad roadbed that stretches from Larkspur to Cazadero through Nicasio in Marin County. The trail runs alongside Lagunitas Creek for much of its length, and there are natural swimming holes scattered along the way where dogs can wade in on warm days—just be ready for a wet dog on the drive home.

The path itself is fairly gentle and wide, following the old railroad grade, which means you won’t deal with steep elevation changes. This makes it accessible whether you’ve got an energetic young dog or an older one who prefers a more relaxed pace. The surrounding landscape shifts as you walk, with rolling hills, oak woodlands, and open grassland creating a pleasant variety. On clear days you get views out toward the Marin hills, and the whole route feels removed from the hubbub of the Bay Area despite being reasonably close to it.

Dogs need to stay leashed here since the trail gets plenty of bike traffic, particularly on weekends. Cyclists move at a decent clip, so keeping your dog close keeps everyone safe and happy. The trail is wide enough that passing usually isn’t an issue, but staying aware helps. Water and shade are somewhat limited along the route itself, so plan accordingly—bring enough water for both of you, especially in summer.

The parking situation varies depending on which trailhead you use. The Nicasio area parking tends to be less crowded than some other access points. If you’re making a full day of it, the trail’s length means you can do a shorter out-and-back walk rather than committing to the entire route. The lack of facilities along the path means you won’t find bathrooms or vendors mid-hike, so do your planning before you head out.