Cycling and climbing by bike the top climbs in the San Francisco North Bay (cycling Marin, Napa and Sonoma counties). Cycling, riding and climbing the top, most difficult, hardest, challenging, extreme, best, scenic, inspiring, bucket list climbs in the San Francisco North Bay Area. These climbs can be viewed via the map below (scroll in to view climbs in particular areas), by a detailed list of the climbs that can be arranged by difficulty, distance (longest climbs in the area), altitude gained, highest elevation (highest summit), average grade (sort the grades by varying distances), lowest start point, etc. You can also view the Top 10, 25 and 50 most difficult climbs in the county. Click on "Climb Page" to jump to the detail page for that particular bike climb.