50 Mile & 50K

TENTATIVE: March 8, 2025

Marin Headlands & Mt. Tam
Sausalito, CA

Congratulations Marin Ultra Challenge runners!


The Marin Ultra Challenge, our premier Marin County long distance trail race, delivers ample hills and sweeping descents. 2024 marks the 11th edition of this tour of some of Marin’s best trails (we lost a couple years due to the pandemic). Meticulous effort went into the design of each course for the MUC; both distances are physically demanding (the 50 Mile has just about 11,000 feet of elevation gain) and exceptionally beautiful. The journey begins at the black sands of Rodeo Beach, and traverses the Marin Headlands, Stinson-facing Mt. Tamalpais and Muir Woods, exhibiting a range of terrain, from exposed fire-roads with incredible coastal and inland views to tight, technical single-track with redwood canopies. There is very little trail overlap, and Jim Vernon, from The Endurables and Hydrapak, spent hours and weekends developing these spectacular custom courses–we are super excited to show it off. You’ll quickly realize why Marin County has become the ultimate trail runner’s destination.

50/50 Challenge: Are you interested in participating in our second annual 50/50 Challenge (Monterey Ultra 50 Miler and Marin Ultra Challenge 50 Miler), you will get on our 50/50 leader board along with all finishers of  the 50/50 get a commemorative hoodie? Sign-up for Monterey Ultra 50 Miler, then reach out to to receive your discount code for the MUC 50 Miler for registration (must already be signed up for MU50 to get the discount, once discount is used there are no refunds, notice to receive a credit must be 3 weeks out from either event you are withdrawing from).

Park Information: Marin Headlands, Mt. Tam State Park, Muir Woods

Start Times:
50 Mile – Saturday, March 8 @ 6:00 AM
50K – Saturday, March 8 @ 7:00 AM

Check-In & Bib Pickup
Early Check-In
Friday, March 7

1:00 PM – 5:30 PM

San Francisco Running Company
247 Shoreline Highway, Mill Valley, CA 94941

Race Morning:
Saturday, March 8 @ 5:15 AM – 7:00 AM
Rodeo Beach Start/Finish

Time Limit: There is a 14.5 hour time limit for the 50 Mile race. 10 hour time limit for the 50K. All runners must be off the course by 8:30 PM.

Parking:  Free parking is available in the surrounding areas to the Start/Finish at Rodeo Beach. Runners may utilize the pullouts along Mitchell Road, along the beach, the annex lot below the Marine Mammal Center, and the Smith Road Parking Lot (Gerbode Valley Trailhead) along Bunker Road. The walk from the Marine Mammal Center lot to the Start/Finish is about 1/3 mile. Parking fills up early, and the later you arrive the further you will have to walk, so please plan your arrival time accordingly.

Golden Gate National Recreation Area
Rodeo Beach
11050 Mitchell Road, Sausalito, CA 94965
Click for Directions

Capacity: The Marin Ultra Challenge has a capacity of 450 runners, across all distances.

Timing:  2024 Marin Ultra Challenge will have live runner tracking! More information closer to event day. Disposable chips are attached to back of each bib number.

Post Race:  We offer a broad selection of sweet and salty snacks, as well as fresh fruit and a diverse line up of pre-packaged food options (chips, cakes, jerkey, etc.). Depending on weather and temperatures we may have chicken noodle soup, and a vegan soup option.

Dog Policy: As much as we love dogs, they are unfortunately not allowed on the Marin Ultra Challenge course. You may have dogs, on leash, at Rodeo Beach.

50 MILE & 50K

Starting at Fort Cronkhite and Rodeo Beach, runners may fill their lungs with fresh salt air before embarking on a journey through some of the best trails the Marin Headlands and Mt. Tamalpais has to offer. Your journey will begins with amazing vistas of San Francisco and the Golden Gate Bridge from the SCA and Julian trails. You’ll soak in the beautiful views of Coastal Trail, the inland buffed single track of the Miwok, descend on the famous Dipsea Trail and tackle one of the toughest climbs around – Willow Camp. You’ll travel along the coast, by Pirate’s Cove, to Muir Beach. Fron there you will cross over to Mt. Tam, climbing to the top of Cardiac Hill then scream down the Dipsea to Stinson Beach. Depart Stinson Beach with the 1,800′ of vertical gain in 1.8 miles on Willow Camp and traverse Mt. Tam along the single-track Coastal Trail, back to the top of Cardiac. Enjoy the tall trees as you pass through Muir Woods, before you climb back into the Headlands on Miwok to the killer downhill of Dias Ridge back to Muir Beach. From there, you’ll quietly pass through the Zen center and up the incredible new Middle Green Gulch hill then traverse through the Headlands all the way back to the finish at Rodeo Beach.


50 Mile (50.2 Miles with 10,550′ Elevation Gain)


Download file: MUC-50-Mile-Rodeo.gpx

50K (31.2 Miles with 6,000′ Elevation Gain)


Download file: -_MUC_2023_-_50K.gpx






Miles 1 – 15 & Miles 39 – 50 / Marin Headlands Miles 15 – 39 / Mt. Tam & Muir Woods


Elevation Charts


Sunrise for Sausalito, CA: 6:31 AM
Sunset for Sausalito, CA: 6:12 PM

Course Composition
The vast majority of the course will be run on moderately technical dirt trails and non-technical fire roads. The hills can be long, and challenging! Hiking/trekking poles are permitted at this venue.

Course Markings
Courses are marked with colored surveyor ribbon, placed approximately every 200 meters along the course. Turns are marked heavily on the inside of the turn, with ~3 ribbons placed just before and just after the intersection. There will also be 8.5″ x 11″ laminated signs and flour arrows on the ground (when allowed) at critical or complicated sections. The detailed course map displays which colored ribbons must be followed for each route. Please keep in mind if you are running a longer distance, you will likely need to follow more than one color while out on the course. The most important course marking is the blue ribbon. Blue ribbons indicate “wrong way” trails. You will see blue ribbons, but do not run past a blue ribbon or you will be heading off course!

Drop Bags and Headlamps
Drop bags will be available at 2 different aid stations (which the 50 Mile will pass a total of 4 times, 50K runners will pass 2 times):
1) Tennessee Valley AS: Mile 10.5
2) Cardiac AS: Mile 19.8 (50 Mile Only)
3) Cardiac AS: Mile 29.3 (50 Mile Only)
4) Tennessee Valley AS: Mile 45.8

All drop bags must be left at the designated spot near the Finish line by 6:00 AM.

Drop bags will remain at each aid station until the aid station closes, unless they are placed by the “Return to Finish Area” sign, which will be available at both Tennessee Valley and Cardiac Hill. If bags are not placed by the “Return…” sign, they will NOT be returned to the finish area!

Crew/Pacer Information
Runner crew is able to reach every aid station, but must abide by posted parking rules. There is no parking available at the Deer Park Aid Station. Crew must hike 1/2 miles to reach the Cardiac Aid Station.

Pacers may join runners at any time after their second pass through Cardiac Aid Station, mile 29.3.

Aid Stations
Inside Trail Racing aid stations are replete with an optimal variety of glycogen-replenishing, electrolyte-replacing products. The following is a list of some of the foods and beverages each aid station may provide: Gu Energy gels and chews, Gu Stroop-Waffles, trail mix, pretzels, potato chips, Oreo cookies, Pop Tarts, PB&J sandwiches, M&M’s, Mike & Ike’s, boiled potatoes with salt, Coke, Mountain Dew, Ginger Ale, water, Skratch Hydration Mix, salt tablets, and seasonal fresh fruit. Aid stations are also equipped with general first aid items (but no anti-inflammatory medicine).

As distances between aid station vary, we strongly encourage all runners to carry at least one 20oz bottle during their run.

Skratch Hydration is mixed so that it contains 80 – 100 calories per 20 fluid ounces.

Cupless Event
This a cupless event, meaning aid stations will not have paper cups available for runner use. Each runner will be responsible for carrying their own water bottle or reusable cup. Reusable cups are made of silicone, are collapsible, and easy to carry with you while you run. Going cupless will keep hundreds, or thousands, of paper cups from being thrown away or left littering the trails. Read more about our cupless events here. Reusable cups by HydraPak will be available for purchase at each event for $5.

Run with us at the MUC!


Without the support of enthusiastic and caring volunteers producing our races would not be possible. Volunteers of all ages and abilities help with setup, check-in, aid stations, course marshaling, timing, and post-race food. Volunteering is a fun, novel way to experience races, play in the outdoors, and spend time with friendly people.

All volunteers receive a free race T-shirt, free food, and the ability to earn credit toward a future Inside Trail Racing event, commensurate to the amount of time worked.

To volunteer for this year’s event, please submit our online volunteer form.


★ In an effort to promote healthy competition, overall awards are determined by gun time (the first 3 men and women across the finish line). Age group awards are determined by chip time (the time from crossing the start line to crossing the finish line).

The top 3, male and female, finishers in the 50 Mile event will receive a trophy, a pair of La Sportiva Mountain Running shoes as well as the following cash awards:
     ● 1st – $500
     ● 2nd – $250
     ● 3rd – $150

The top 3, male and female, finishers in the 50K event will receive a trophy, and a pair of La Sportiva Mountain Running shoes.

All finishers will receive a custom medal with the race logo.

All 50 Mile and 50K finishers will receive a pint glass with the race logo.

The Dead Last Finisher (DLF) in each even will receive a custom award.

Age-group medals (3 deep) will be awarded in the following categories, for both males and females:

     • 13 and under
     • 14 – 19
     • 20 – 29
     • 30 – 39
     • 40 – 49
     • 50 – 59
     • 60 – 69
     • 70 and over


All registered runners will receive a District Perfect-Tri tri-blend fabric shirt. This tee is made with top-of-the-line sportswear technology to heighten performance during your toughest workouts. With sun defense, moisture-wicking technology, quick stain release, and comfortable fit, this tri-blend performance crew serves the needs of every athlete. It’s the perfect year-round choice for outdoor sports and exercise. Get the most out of your workout with this tough, hardworking tee.

     ● 4.5-ounce, 50/25/25 poly/combed ring spun cotton/rayon, 32 singles
     ● 1X1 rib knit neck
     ● Shoulder to shoulder taping
     ● UPF 30

To be guaranteed your shirt size, you must register by February 25, 2023.


Distance Name Age Year Time
50 Mile – Male Ryan Neely 26 2016 6:39:38
50 Mile – Female Kimberly O’Donnell 26 2016 8:23:12
50K – Male Jeff Mogavero 24 2018 3:42:51
50K – Female Jennifer Schmidt 31 2023 4:03:44
25K – Male David Roche 27 2016 1:33:21
25K – Female Danielle Moreno 23 2016 1:46:55


JUNE 3, 2023


MARCH 12, 2022

MARCH 9, 2019
25K Overall
50K Overall
50 Mile Overall


Results for previous years can be viewed on Ultrasignup.


ITR Refund Policy:

Entry fees to our trail runs are non-refundable in all cases, and we do not offer credits, transfers, or deferrals to future races except as described below. Only registered runners can participate in our races, and you cannot exchange your entry with anyone else in any case.

We are happy to issue a credit worth 50% of your original race fee toward a future Inside Trail Racing event if we receive your cancellation at least 3 weeks prior to the race. Credits will expire 1 year after the date issued. There will be no credit provided if a cancellation is made within 3 weeks of the race.

While we understand that last-minute injuries, conflicts, emergencies, deaths, and other unfortunate events affecting registered runners can happen and may impact your plans for participation, we must adhere to our cancellation policy stated above and cannot offer any credits, refunds, transfers, or deferrals in any of these cases.

If the situation does arise where ITR must outright cancel an event for any reason, there will be no refunds. This could include earthquakes, floods, extreme weather, unsafe air quality, pandemics, or any other “Act of God”. ITR at its sole discretion may choose to offer future race credit or deferrals in these force majeure situations, depending on the circumstances and how close to the race date the event was cancelled. We will communicate with all registered runners as soon as possible regarding the cancellation and any pertinent information. We do not cancel races due to rain or heat. Due to trail work, closures, or for myriad other reasons, permitting agencies may require changes to the publicized courses at any time prior to an event. This is out of our control, and we therefore will not offer refunds, credits, deferrals, or transfers (except as described below) in such a situation.

If a race location is changed, but still hosted on the same day, we will automatically transfer the registration over to the new venue, or entrants may choose to run the race remotely and we will mail awards. If a race is postponed all entrants will be transferred to the new date.

Please refer to our online FAQ page for answers to other commonly asked questions.







Join Us at Our Next Race!

We would love to see you there

Pin It on Pinterest