The course
The Miwok 100K starts and finishes at the Stinson Beach Community Center and tours the best trails of southern Marin, stitching together the Dipsea, Coastal, Miwok, Bolinas Ridge, Matt Davis, and Randall trails across Mount Tamalpais and the Marin Headlands. It is 62.2 miles with about 11,500 feet of cumulative climbing and a nearly equal amount of descent, on a mix of fire road, flowing singletrack, and a few genuinely technical sections.
Up out of the gate, then the headlands
The race climbs almost immediately out of Stinson Beach, including the early Insult Hill on the Dipsea, before pushing out toward the Marin Headlands and the coastal fire roads and singletrack that define the front half. You gain real vert early while your legs are fresh, and that is the trap on a course like this: the rolling terrain feels runnable, so it is easy to spend energy you will want back later.
The smarter move is to settle your effort here, power-hike the steep punchy climbs with purpose, and let the runnable rollers come to you. The early cutoffs mean you do have to keep moving with margin, but margin and over-racing the first 20 miles are not the same thing.
Exposure, views, and the SCA Trail
Out toward the bridge, the rugged SCA Trail delivers the famous Golden Gate views on technical, exposed coastal terrain. Much of the headlands running is open to sun and wind, so even in cool, foggy May conditions the exposed ridgelines can swing warm and dry out faster than you expect. This is where coastal exposure quietly raises your fluid and sodium needs.
These open sections are also where line choice and footing matter. Stay efficient on the technical bits, keep your effort honest on the climbs, and treat the exposed stretches as a place to manage temperature and hydration actively rather than hammer pace.
Bolinas Ridge, Randall, and the back half
The back half climbs the long Bolinas Ridge before the out and back down to the Randall Trailhead near mile 49, the final major resupply with roughly a dozen miles left to the finish. The Randall descent and climb back, plus the Bolinas Ridge sections, are where a day that started too fast turns into a grind, and where the strict, permit-driven Randall and Bolinas Ridge cutoffs can end a race that fell behind early.
Runners who paced the front half with discipline still have legs here. Those who burned matches on the early rollers feel every remaining climb. The constant rolling profile means there is no flat recovery to coast on, so banking effort early almost always backfires.
The technical finish: Matt Davis
The race comes home with a technical descent on the Matt Davis Trail, full of roots and rocks, dropping back down to Stinson Beach. After 50 plus miles of rolling vert, this rooty, rocky downhill demands real attention from tired legs and trashed quads, and it is no place to be careless chasing a finish time.
Because the whole course gives back about as much as it climbs, downhill running is a genuine crux. Train your quads for sustained and technical descending so the Matt Davis finish, and every descent before it, is something you can run rather than survive.
Aid stations and cutoffs
The course is supported by a series of aid stations with water, electrolyte fluids, and food, including Cardiac, Muir Beach, Tennessee Valley, Bolinas Ridge, and the Randall Trailhead, several of them hit twice as the route loops out and back. The overall time limit is 15 hours 30 minutes.
The early cutoffs are strict and the late ones at Randall and Bolinas Ridge are tied to State Parks permits, so they are enforced firmly. The outbound Tennessee Valley cutoff near mile 13 lands only about three hours into the race, so the front half cannot be hiked casually. Check the official Miwok 100K cutoff chart for the current edition and build your pacing plan backward from those times, with a buffer.
Pacing strategy for the Miwok 100K
A relentlessly rolling 100K with strict early cutoffs rewards an even, honest effort and punishes anyone who races the runnable front half. Pace this course by effort and by grade, not by a single flat-ground number.
Pace the rollers by grade, not by clock
With about 11,500 feet of gain spread across constant short climbs and rollers, your moving pace will swing all day, and that is correct. Power-hike the steep punchy pitches efficiently and run the gentler grades and descents. Trying to hold one steady minutes-per-mile number across this terrain is how you overcook the climbs and arrive at Matt Davis with nothing left.
Use our free grade-adjusted pace calculator to translate your flat fitness into honest effort targets for the Miwok climbs and rollers, so you know whether you are pacing the vertical sustainably or burning matches you will need in the back half.
Beat the early cutoffs without over-racing
The hardest balance at Miwok is real: the early cutoffs, like the roughly three-hour outbound Tennessee Valley gate near mile 13, demand that you run the front half with margin, but over-racing those opening miles is exactly how runners blow up before Bolinas Ridge. The answer is a planned, even effort that keeps you safely ahead of the clock without spending your descents.
To set a finish goal that actually accounts for all that rolling vert, use our vert-aware race time calculator. It factors the climbing into your projected finish and splits, so you can plan cutoff buffers off a realistic time instead of a flat-course guess that the Marin trails will quietly demolish.
Protect your quads for the descents
Because the course descends about as much as it climbs and finishes on the technical Matt Davis Trail, downhill running is the hidden crux. Run the early descents controlled and light rather than letting gravity hammer your legs, and your back half, and that final rooty drop to the beach, will be dramatically better.
If you want to know how your fitness from a recent race translates to a rolling mountain 100K like this, our race equivalent calculator helps you reality-check your goal before you commit to a finish time.
Fueling strategy for the Miwok 100K
A fast, all-day effort on exposed coastal terrain makes fueling and hydration as decisive as fitness. Marin's variable May weather is the wildcard, so build a plan you can flex to the day.
Carbs: ramp to the high end, on a trained gut
For an effort this long, target roughly 60 to 90 grams of carbohydrate per hour, leaning toward the high end once your gut is trained to handle it. Use a glucose-plus-fructose blend so you can absorb more than a single sugar allows, and rehearse your exact hourly carb number on long training runs so 80 to 90 g/h feels routine, not experimental, by race day.
On a course with no flat recovery, the steady drip of fuel matters. Keep eating on the climbs and through the technical sections, because falling behind on calories early in a rolling 100K is hard to claw back late.
Sodium and fluid: flex to the conditions
Bias your sodium roughly into the 400 to 700 mg per liter of fluid range depending on how heavily you sweat, and carry enough to cover the gaps between aid on the exposed headlands sections. Early May in Marin can be cool and foggy or warm and dry on the open ridges, sometimes in the same race, so dial fluid to the actual conditions rather than a fixed number.
Dial in a personalized plan with our free ultra fueling calculator: enter your weight, your goal time, and the expected heat, and it gives you a carb, sodium, fluid, and caffeine prescription per hour built for the Miwok duration and conditions. Then go test it in training.
This guide is for planning and training purposes and reflects publicly available information about the Miwok 100K. Race details, including the date, course, aid stations, and cutoffs, can change year to year, and the official 2027 date had not been published as of this writing. Always confirm the current specifics on the official Miwok 100K race website before you train or travel.