About Marin County - Marin County is just north of San Francisco via the Golden Gate Bridge. The only land border is with Sonoma County to the north and east. To the west is the Pacific Ocean. When it comes to trail safety, there are four reasons why you can't rely on our books or our web information. First, trails change.
Hillsides erode, trees fall down and signs change.
In winter, some trails are impassable. Second, no matter how descriptive our map or text is, it can't describe every feature, root, rock or rut. Third, there are errors in our descriptions. Fourth, our descriptions may not apply to you. When we say a ride is easy or moderate, it may, in fact, be too difficult.