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⏵ Course guide · California ultra

Mt. Tam Trail Run 50K Course Guide

Inside Trail Racing’s Mt. Tam Trail Run is the Bay Area 50K that runs the best trails on Mount Tamalpais, and it does not ease you in. You start at sea level on the sand at Stinson Beach and climb hard up the Steep Ravine and Dipsea trails toward the top of the mountain, then string together Coastal, Miwok, Bootjack and more before dropping back down. I will walk you through the course first, then give you a pacing and fueling plan that fits the climbing and the cool coast. There are free calculators along the way to dial in your own numbers.

⏵ At a glance

Mt. Tam Trail Run 50K quick facts

Date
Saturday, November 7, 2026
Location
Stinson Beach, Mount Tamalpais, Marin County, CA (Mt. Tamalpais State Park / Golden Gate NRA)
Distances
50K (about 30 mi) · 30K (about 18.5 mi) · Half (about 13 mi) · 10K (about 6.8 mi)
Elevation gain
50K: about 6,000 ft · 30K: about 3,900 ft · Half: about 2,800 ft · 10K: about 1,600 ft
50K start
7:30 AM (30K also 7:30 AM, Half and 10K at 8:00 AM)
Cutoff
50K and 30K: 8 hr 30 min, all runners off the course by 4:00 PM
Format
Cupless race (carry a bottle), small prize purse for the top three
Qualifier
No Western States, UTMB, or Hardrock qualifier status listed by the race

These facts come from the official race site and UltraSignup. Check the current date, cutoffs, and aid stations in the race-day details before you commit. Race logistics change year to year.

The course: where Mt. Tam is won and lost

The 50K is about 30 miles with roughly 6,000 feet of climbing, run on a loop of Mount Tamalpais’ marquee trails out of Stinson Beach. Steep Ravine, Dipsea, Coastal, Miwok, Bootjack, and more, mixing technical dirt singletrack with non-technical fire road. The thing to understand going in is that the hard climbing comes early, the footing is real, and the descents are steep enough to wreck your legs if you are careless.

The climb out of Stinson: sea level to the top of the mountain

You start on the coast at Stinson Beach, basically at sea level, and the day’s big work is the long climb up toward the high country on Mount Tam. A lot of it goes up the Steep Ravine and Dipsea trails, which are exactly as steep as they sound, including the famous Dipsea wooden steps through redwood and fern. This is where the race is decided. Hike the steep pitches with purpose, keep your heart rate honest, and do not race the early grade because it feels good. People who power up this climb in the first hour pay for it badly later.

Higher up the course rolls through more open terrain on Coastal, Miwok, and Bootjack with big ocean views and real exposure on the ridgelines. The grades ease compared to the ravine, but you are still gaining and losing chunks of vert. Settle into a rhythm you can hold for hours, eat and drink on the climb, and treat the top as the halfway point of the effort, not the finish line.

The descents: steep, technical, and hard on the quads

What goes up out of Stinson has to come back down, and the descents here are no joke. You drop on steep, rooty, rocky singletrack and back down the Dipsea steps, which are slick and awkward when your legs are already tired. This is fast free time if you trained for it and a slow, painful shuffle if you did not. The runners who blow up here are the ones who hammered the climb and never practiced controlled downhill running.

Practice steep, technical descending before race day, on tired legs if you can. Being able to keep your feet moving and stay relaxed going downhill late in the race, when your quads are cooked, is honestly what separates a good finish from a death march to the 4:00 PM cutoff.

Aid, the cupless rule, and the long climbs between stations

The 50K passes through several aid stations on the mountain (Muir Beach, Cardiac, and Deer Park are among the named ones), well stocked with the usual trail spread plus real food. This is a cupless race, so you carry your own bottle or soft flask, no paper cups at the aid stations. Inside Trail suggests carrying at least a 20-ounce bottle, and that is good advice given the climbing between stops.

Plan to top off fluid and grab calories at every station, because the gaps include sustained climbs where you burn through what you are carrying. Note that some spots inside the Golden Gate NRA have restrictions on certain gels, so read the current aid-station sheet and do not assume your exact product is stocked. Carry what you know your gut likes.

Pacing strategy for a steep, climb-early 50K

With about 6,000 feet of gain front-loaded into the climb out of Stinson and steep technical descending on the way home, Mt. Tam is about managing effort, not hitting a pace chart. Run the climb by feel, not by your flat-ground splits.

Pace the climb by grade, not by the watch

Your flat-ground pace is meaningless on the Steep Ravine and Dipsea climb. What matters is grade-adjusted effort, so hold a steady output you can sustain up the grade and power-hike the steep steps without feeling like you are losing the race. The classic Mt. Tam mistake is running the early climb too hard because the legs feel fresh, then falling apart on the descents. Use a grade-adjusted pace to turn your real fitness into honest climbing and descending targets, and you will not torch the first half.

Build a vert-aware finish prediction against the 4 PM cutoff

Do not guess your Mt. Tam finish off a flat road 50K time. The 6,000 feet of climbing, the technical Dipsea-step descents, and the slow ravine footing all add real time on the clock. A vert-aware finish prediction that accounts for this course’s climbing gives you a realistic window and lets you work backward into the 8.5-hour cutoff and the 4:00 PM off-the-course deadline, so you actually know how much buffer you have at each aid station instead of guessing.

⏵ Free tools to pace this course

Fueling strategy for the duration and the climbs

Most runners are out on the Mt. Tam 50K for somewhere around 5 to 8.5 hours, with sustained climbs that burn through calories and a cupless aid setup where you carry your own fluid. That makes carbohydrate, sodium, and fluid just as important as fitness.

Carbs: steady and trained

For a 5 to 8.5 hour effort, aim for around 60 to 90 grams of carbohydrate per hour, and only push the higher end if your gut is trained for it. The long climbs make it easy to forget to eat, so set a schedule and keep your intake steady and easy to get down rather than gambling on big late doses. Practice your exact race-day carb rate on hilly long runs so 70 to 90 grams an hour feels normal, not like an experiment on race morning.

Sodium and fluid: carry your own and plan for the climbs

This is a cupless race, so you carry a bottle or flask and refill at the aid stations, and the climbs between stops mean you should leave each one topped off. On sodium, most runners land somewhere around 300 to 600 milligrams per liter of fluid, and you push higher if you are a heavy or salty sweater, even on a cool coastal day. The fog and cool air can mask how much you are actually sweating on the climbs, so do not under-drink just because it feels mild. Weigh yourself before and after a long hilly run to find your real sweat rate, then build the plan around your own number.

⏵ Build your fueling plan

Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and the Mt. Tam climbing with the free ultra fueling calculator. Browse the rest of the free running tools at the tools hub.

⏵ Train for it with Summit Line

Get a race-day plan built around YOUR fitness, this exact Mt. Tam course profile, and your projected splits. Summit Line reads your real training, builds a plan for the climbing, and rehearses your fueling so race day is something you execute, not guess at.

Start free →Explore the demo

Mt. Tam Trail Run 50K FAQ

How hard is the Mt. Tam Trail Run 50K?

It is a genuinely tough mountain 50K, not a forgiving one. You cover about 30 miles with roughly 6,000 feet of climbing on Mount Tamalpais’ most famous trails, and the whole thing starts with a long, steep haul straight up out of Stinson Beach at sea level. The footing is real Marin singletrack with the wooden Dipsea steps, roots, and rock, so it asks for strong climbing legs, careful descending, and a respect for the 8.5-hour cutoff. If you train the vert and the technical terrain it is very doable, but nobody runs a fast flat-50K time here.

How much climbing is in the Mt. Tam Trail Run 50K?

The 50K has about 6,000 feet of total elevation gain over roughly 30 miles, per Inside Trail Racing’s course info. The defining feature is the early climb from Stinson Beach (sea level) up toward the high country on Mount Tam, much of it on the steep Steep Ravine and Dipsea trails, then rolling singletrack and fire road up high before you drop back down. The 30K has about 3,900 feet, the half marathon about 2,800 feet, and the 10K about 1,600 feet, so even the short options are hilly.

What are the cutoff times for the Mt. Tam Trail Run 50K?

The 50K (and the 30K) carry an 8 hour 30 minute time limit, and the race wants all runners off the course by 4:00 PM. With a 7:30 AM start that lines up to the 8.5 hours. There are aid-station checkpoints along the way, so confirm the current intermediate cutoffs in the race-day details before you start and do not plan to save all your buffer for the finish.

What trails does the Mt. Tam 50K use, and what is the terrain like?

The course strings together some of the best trails on the mountain: Steep Ravine, Dipsea, Coastal, Miwok, Bootjack, and more, with a mix of technical dirt singletrack and non-technical fire road. Expect the famous Dipsea wooden steps, redwood and fern shade in the ravines, rooty and rocky footing, and big open ocean views from up high. It is classic Marin trail running, which means steep grades both up and down and footing that rewards paying attention.

What is the weather like at the Mt. Tam Trail Run in November?

Early November on the Marin coast is usually cool and can be damp. Mornings at Stinson Beach often start foggy and chilly near the ocean, then it can clear and warm up as you climb above the marine layer, with strong sun and big exposure on the open ridgelines up high. Trails can be wet, muddy, or slick in the redwood ravines if it has rained, and the Dipsea steps get slippery. Dress for a cool, possibly foggy start you can shed, and do not assume it stays cold all day.

Is the Mt. Tam Trail Run 50K a good first 50K?

It can be a great goal race for a well-prepared first-timer, but it is not an easy place to start. The 6,000 feet of climbing, the steep technical descents, and the Dipsea steps all reward specific prep: time on steep singletrack, practice hiking long sustained climbs, and real downhill running so your quads survive the back half. If you train the vert and the terrain, the 8.5-hour cutoff gives most committed runners room to finish, and the shorter 30K, half, and 10K options are good stepping stones.

This guide is independent and for planning only. The course details, dates, cutoffs, and aid stations come from public sources and can change year to year, so confirm the current specifics with the official race before you register or run. The fueling and pacing advice is general and not medical advice.