There is no water, restrooms or garbage cans on the trail.
This is an out and back trail that runs along the crest of the long ridge that extends from the high point of San Bruno Mountain, almost to the Bayshore highway. On a clear day, there are great views in all directions, but especially when looking northeast towards San Francisco and the Bay Bridge. In the spring, there are beautiful wildflower displays.
Note: there is no clear trail that drops the last 300 feet to the Bayshore Highway. There is no parking on the highway, and at the bottom, that area is marked "No Trespassing."
On the low-resolution park map, this tail appears to be fairly easy. It is a wide road. The first two miles go from San Bruno Mountain, at 1,314 feet, to the last high point at 1,044 feet. However, in between, there are almost continuous ups and downs and some are steep and rocky. Heavy-duty mileage stakes mark every half mile. From the last high point, just after the 2.0 mile marker, the trail drops about 500 feet over the next 0.6 miles. You may want to turn around and skip this last section.
There are several trails that connect from Brisbane to the Ridge Trail
. There is no entrance fee when you use these trails, but they all involve long steep climbs. There is limited parking at these entrances. Parking areas are marked with white lines and signs which say that you must park to the right of the line. It is a tight squeeze. Don't park in a way that bothers the local residents or we may end up with local residents only parking.
My favorite entrance is the connector trail that starts at Firth Park. From the bottom of the park, hike up the canyon on a rough trail leads to T-junction with an almost level trail. Turn left. After a short distance, turn right at the junction with a trail that climbs steeply up to connect with the Ridge Trail
at the 2.5 mile marker. You can avoid some of the climb in Firth Park by driving 100-200 yards east up Sierra Point Road and parking just below Humboldt Rd. Then turn right on Humboldt Road and continue past its end until you connect with the Firth Park Trail.
Another good connector starts from the end of what is labeled Trinity Road on Google maps, although the locals call it the Kings Road entrance and the street sign at the junction seems to label it as Kings Road. At the cul de sac, a fire-road climbs steeply up the mountain to connect with the Ridge Trail
at about the 1.65 mile point.
Because of its relative isolation, it has a number of rare plants and butterflies. The peak flower season is a month or two earlier than in the Golden Gate National Recreation Area. Large ravens are very common.