Route: San Fran Bay Circumnav via Bay Area Ridge Trail (CA)

Patrick Martin submitted this 320-mile Route which circumnavigates the San Francisco Bay mostly via the Bay Area Ridge Trail.

From https://ridgetrail.org/
"History--Thirty years ago park visionary William Penn Mott, Jr., who served as Director of the National Park Service as well as East Bay Regional Park and California State Parks, brought forth a big idea. He wanted to unite the ridges encircling the Bay Area into one continuous park with a 550-mile Ridge Trail. Ultimately the vision included connecting the Ridge Trail, and the metropolitan center it served, to the Sierra Nevadas.
In 1987, the Greenbelt Alliance, the Golden Gate National Recreation Area, the National Park Service as well as citizen advocates came together to help form the Bay Area Ridge Trail Council. Thanks to their pioneering leadership the Ridge Trail is growing mile by mile.
Progress.
Trail Progress: The first Ridge Trail segment was dedicated in May 1989. During the first few years, the Bay Area Ridge Trail Council made rapid progress, dedicating 200 miles of existing trail on public lands by 1995.
Today, 375 miles are open and ready to explore 80% of which is open to bikes and horses. Bit-by-bit continuous sections are being knit together to provide true thru-hike (or bike, or ride!) opportunities. On our Western Ridge we have an 80-mile stretch from northern Marin to Highway 92 and on our Eastern Ridge we have a 43-mile connected stretch from El Sobrante to Union City. "

The route I put together skips the northern most sections and cuts over on Hwy 37 as it would require a lot of roads between short sections of trial. Otherwise, I tried to follow the Bay Area Ridge Trail as closely as possible. 

Update 4/25/25 -- see BART_2025.gpx file and updates below -- updates provided to avoid crossing through private property.

2025 Route Updates
As mentioned by many in the comments below, due to private property, trespassing, and general access issues— I’ve made some updates to the original route. There are three key sections that posed issues. I’ve listed them below and described the alternate route. Below those are some additional notes that I thought might be helpful. Please note: the GPX file may still have some minor inaccuracies, so make sure to do your research and go section hike the route before sending it on an FKT attempt!
I have section-hiked the entire route more than once in preparation for my FKT, as well as hiked it continuously in my recent FKT effort, so I can confirm all of the bypasses “go” and that they are logical alternates to the problematic sections of the original route.

1) Novato
The original route cut north onto Burnt Ridge Fire Road (roughly 38.05901, -122.60419) which is property of H Ranch with no public access. Instead, continuing on Big Rock Ridge Fire Road allows one to stay on publicly accessible land, eventually cutting north for a pleasant stroll through Novato. The walk through town is mainly residential, but also goes down the main drag which allows for an easy resupply (Safeway or Trader Joes) before linking with the original route.

2) Niles
In the East Bay, just north of Fremont, is another section where the original route cuts through private property with no public access. Instead of taking a sharp left (and then jumping a gate that says “AREA CLOSED NO ENTRY”) at the junction around 37.63391, -121.98889, bear right (west) onto the Whipsnake Trail and proceed down precipitously towards civilization through stunning terrain with excellent views. From here, pass a bathroom and a working faucet and then bear south on Mission Blvd for a few miles until rejoining the original route. These urban miles, while not particularly striking, do offer some good gas station resupply options.

3) Fifield-Cahill Ridge
Technically, this section of trail has limited public access, but the near-impossibility of securing a permit (which, even if secured, is subject to frequent cancellation) and the challenge of lining up a docent-guided walk with an FKT attempt make it ill-suited for an FKT. So instead of bearing left at 37.50518, -122.35828, one can continue straight along the 92 and then hang a left on the 35 North. Shortly after making this left, the Sawyer Camp Trail, a lovely walking path paralleling Lower Crystal Springs Reservoir, is picked up. This trail can be followed for miles all the way to the northern tip of San Andreas Lake. A short jaunt through a neighborhood brings
hikers back to the original route. I think both of these options “go” in terms of the FKT, if someone is really adamant about staying on the Ridge Trail proper, and is willing to play the logistical game of lining the guided walk through Fifield-Cahill Ridge.

A note on the Highway 4 Crossing

Around 38.00952, -122.20651, one is tasked with crossing Highway 4. There are two options, and I have hiked both of them. One is the eastern option, which allows you to cross under a tunnel for the westbound side of the 4, and then you can play frogger to get across the eastbound side. The other is to bear south at the saddle shortly before the crossing, walk under the westbound side of the 4, and then cross over the eastbound side via the train tracks. They are roughly the same distance, I slightly preferred the latter.

Miscellaneous
A few other small updates to the route have been made that mainly involve staying on the true Ridge Trail where possible. The trail is actively being developed and hopefully this FKT will be more-and-more on the Ridge Trail as the trail is completed. The next section likely to open is a few miles paralleling the 35 before it joins the 92, which will be a welcome alternative to the unpleasant shoulder walk along the 35! I hope these updates help people get out there and hike the Bay Area Ridge Trail, whether or not they are going for the FKT. It really is a stunning route, and I’m certain you will be blown away by the amount of incredible green space and wilderness there is in, of all places, the Bay Area.

-Mustang