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Ultras · US · CA

Marin Ultra Challenge

50K · 30.8 miles
Registration open
Registration is open on UltraSignup.
Race dateMarch 13, 2027
Start7:00am
Whenin 140 days

Who's going to Marin Ultra Challenge?

I'm running itPlan your weeks and your aid station times I'm crewingWhen to leave, where to park, at every stop I'm pacing or cheeringAsk your runner for their Out Here link

Free. You can start with nothing.

Official website Entry Aid stations Crew access Notify me if this race changes
Free, and always will be. NavRun makes money from race-day planning for runners who want it, never from this. Ultras change constantly, sometimes the morning of. Always confirm with the race director and the official website before you rely on anything here.
Distance
30.8 miles
Climb
6,310 ft
Descent
6,311 ft
High point
not checked yet
Time limit The race
10:00:00
Aid stations
7
Started
not checked yet
Finished
not checked yet
Finish rate
not checked yet
The course

Where it goes loop · 7 aid stations · rust marks a stop your crew can reach

Course line from the race's own GPX. Source file. Recorded 2025.

Starts and ends at Rodeo Beach. The route passes Tennessee Valley twice and Muir Beach twice, with Conzelman early on, and finishes back at the beach.

The race

What this one is

A 50 Mile and a 50K that start and finish at Rodeo Beach in the Marin Headlands, with a route through the Golden Gate National Recreation Area, Muir Woods and Mt. Tamalpais State Park. Exposed fire roads with coastal and inland views, tight technical singletrack under redwoods, and a lot of hills.

Getting in

Getting in Entry, lottery and what the race asks of you before race day.

Lottery
not checked yet
Lottery opens
not checked yet
Lottery draw
not checked yet
Field cap
not checked yet
Registration
UltraSignup ultrasignup.com
Qualifying
not checked yet
Minimum age
not checked yet
Transfers
No ultrasignup.com
Deferrals
not checked yet
Crew access, pacers and drop bags

The rules that shape your day Anything marked "not checked yet" is a gap in what we hold, never a no from the race.

Crew allowed
Yes insidetrail.com
Vehicles per runner
not checked yet
Pacers
No insidetrail.com
Muling
not checked yet
Drop bags
not checked yet
Cupless
Yes insidetrail.com
Course marking
Fully Marked insidetrail.com
Night running
not checked yet
Dogs
Not allowed insidetrail.com
Headphones
Allowed insidetrail.com
Crew rules
Crew may help only within 30 meters of an aid station and must follow the parking rules and instructions at each one. Crew can reach every aid station except Deer Park. insidetrail.com
Pacer rules
not checked yet
Drop bag rules
not checked yet
Cutoff philosophy
Hiking is part of the race: most runners, including some elites, hike the big hills. Walk or even crawl to the finish, as long as you reach each aid station before its cutoff. insidetrail.com
Aid stations

Every stop, and what you get there ● yes   ○ no   ? nobody has checked   – does not apply to this race

Mile Station Cutoff Crew access Bag Pacer Med To next
0.00 Start (Rodeo Beach)
NoneSignal wrong?
 ? ? ? ? ? 5.80
5.80 Conzelman
NoneSignal wrong?
 8:52am ● ○ ? ? 4.70
10.50 Tennessee Valley
NoneSignal wrong?
 10:25am ● ? ? ? 4.20
14.70 Muir Beach
NoneSignal wrong?
 11:45am ● ○ ? ? 6.90
21.60 Muir Beach
NoneSignal wrong?
 2:00pm ● ○ ? ? 5.00
26.60 Tennessee Valley
NoneSignal wrong?
 3:35pm ● ? ? ? 4.20
30.80 Finish (Rodeo Beach)
NoneSignal wrong?
 5:00pm ? ? ? ? ?
Driving your crew

Getting your people there 5 stops with directions the race published.

Conzelman mile 5.80 cutoff 8:52am

Head east on Mitchell Road 0.5 mi; Merge onto Bunker Rd. 1.8 mi; Turn right on McCullough Road 0.9 mi; At the traffic circle enter parking area 0.0 mi. The trip takes 3.2 miles and about 9 minutes. Destination: Intersection of Coastal Trail and Conzelman Road parking area.

insidetrail.com
Tennessee Valley mile 10.50 cutoff 10:25am

Head east on Mitchell Road 0.5 mi; Merge on to Bunker Road 3.5 mi; Turn right on to Alexander Ave 0.2 mi; Turn left and merge on to US-101 North 3.6 mi; Take exit #445B CA-1 Mill Valley/Stinson Beach onto Highway 1 (CA-1) 0.7 mi; Bear left onto Tennessee Valley Rd. 0.1 mi; Bear right to stay on Tennessee Valley Rd. 0.2 mi; Bear left to stay on Tennessee Valley Rd. 1.3 mi. The trip takes 10.5 miles and 24 minutes. Destination: Tennessee Valley Trailhead.

insidetrail.com
Muir Beach mile 14.70 cutoff 11:45am

Head east on Mitchell Road 0.5 mi; Merge on to Bunker Road 3.5 mi; Turn right on Alexander Ave. 0.2 mi; Take left ramp on to Redwood Hwy (US-101 N) toward Eureka. 3.5 mi; Take exit #445B CA-1/Mill Valley/Stinson Beach onto Highway 1 (CA-1) 1.0 mi; Turn Left to stay on CA-1 N 5.7 mi; Turn left on to Pacifica Way 0.2 mi. The trip takes 14.5 miles and 35 minutes. Destination: Muir Beach Parking Area.

insidetrail.com
Muir Beach mile 21.60 cutoff 2:00pm

Head east on Mitchell Road 0.5 mi; Merge on to Bunker Road 3.5 mi; Turn right on Alexander Ave. 0.2 mi; Take left ramp on to Redwood Hwy (US-101 N) toward Eureka. 3.5 mi; Take exit #445B CA-1/Mill Valley/Stinson Beach onto Highway 1 (CA-1) 1.0 mi; Turn Left to stay on CA-1 N 5.7 mi; Turn left on to Pacifica Way 0.2 mi. The trip takes 14.5 miles and 35 minutes. Destination: Muir Beach Parking Area.

insidetrail.com
Tennessee Valley mile 26.60 cutoff 3:35pm

Head east on Mitchell Road 0.5 mi; Merge on to Bunker Road 3.5 mi; Turn right on to Alexander Ave 0.2 mi; Turn left and merge on to US-101 North 3.6 mi; Take exit #445B CA-1 Mill Valley/Stinson Beach onto Highway 1 (CA-1) 0.7 mi; Bear left onto Tennessee Valley Rd. 0.1 mi; Bear right to stay on Tennessee Valley Rd. 0.2 mi; Bear left to stay on Tennessee Valley Rd. 1.3 mi. The trip takes 10.5 miles and 24 minutes. Destination: Tennessee Valley Trailhead.

insidetrail.com
Same race, other lines

Other distances and other years

Other distances
50 Miler (50 Mile)
What it looks like out there

Somebody has been out there with a camera the tables say the climb is long. these say what long feels like.

3 people have been out there with a camera or a microphone.

Social account

Inside Trail Racing

Social account
Social account

Inside Trail Racing

Social account
Official channel

Inside Trail Racing

Official channel
All (3) Official channel (1) Social account (2)

These are other people's work and we link straight to them. Watching costs nothing and needs no account. More of them: every race we hold, on film.

Add to this page

What you know every one of these is read by a person before it changes anything

Ran this race? Tell the next runner what you know.

Nobody sees it until we have read it. No account, no sign-in.

Leave blank if it applies to the whole race.

Leave blank if it is not about one particular stop.

Optional. Something like “Cal Street, mile 62 to 78”.

Write it the way you would say it to someone at the start line.

Optional, and it decides nothing. It only tells the next runner where this is coming from.

Optional.

Optional, and never shown on the page. Only so we can ask you a question about this note.

Leave this field blank.

See something wrong or out of date? Suggest an edit.

This changes nothing on the page on its own. Somebody checks it against the race first.

Optional. Filled in for you when you start from a specific line on the page.

Copy it as it appears, so we can find it.

The corrected value.

Required. Where it came from: the race email, the runner manual, what you saw on the day.

Optional.

Optional. A screenshot or a photo of the sign works.

Optional, and it decides nothing.

Optional.

Optional, only so we can come back to you about this correction.

Leave blank if it is about the whole race.

Leave blank if it is not about one particular stop.

Leave this field blank.

Seen a course preview or a film of this one? Send it over.

Somebody watches it before it goes anywhere near this page. What we are after is footage of this course, on the ground. If it would be just as true of any other race, it is not this.

Required. A line is plenty. Where the climbs are, what the footing does, what the last twenty miles look like.

Optional, and it decides nothing.

Optional.

Optional, and never shown on the page. Only so we can ask you a question about this one.

A YouTube link, a race report, a photo gallery, whatever it is.

Optional, and we credit them on the page.

Leave this field blank.

Have the GPX? Send us the link.

We want the address of the file the race publishes, not the file. We download it from there so the page can say where the line came from.

The page or file on the race's own site.

Optional, and only so we can ask you a question about it.

Are you the race director? Get in touch and we'll make it right.

We read every one of these and we write back. Every fact here carries the source it came from, and the way a wrong one gets fixed is a person checking it against what you tell us.

Required, because this is a conversation and we write back.

Tell us what is wrong, out of date, or missing on this page. We read every one of these and we will get back to you.

Optional.

So we know who we are writing back to.

Optional. Director, assistant, comms, whoever you are.

Leave this field blank.

Where this came from. Every fact on this page records its source and when we last checked it: 90 sources for this race. Hover a source link to read the sentence it came from.
33% of what we track for a course is filled in. The rest says "not checked yet" rather than guessing.
See something wrong or out of date? Suggest an edit
Ran this race? Tell the next runner what you know
Were you out there? Say which stops a text got out from
Got footage of this course? Send us the link
Are you the race director? Get in touch and we'll make it right.
Anything else: [email protected]

Ultras change. We will tell you when this one does.

Cutoffs move, races get postponed, lotteries open and close. We read the race's own sources and record where every fact came from. Put your email in and we will send you what changed, and where we read it.

No account, and nothing to cancel.

What happens to your email. Nothing else. I do not sell it, and I will not send you anything except this race changing. One click gets you out.

I keep this catalog because the information is scattered and hard to trust. Telling you when it moves is the same job.

Ultras change. We will tell you when this one does.

Cutoffs move, races get postponed, lotteries open and close. We read the race's own sources and record where every fact came from. Put your email in and we will send you what changed, and where we read it.

No account, and nothing to cancel.

What happens to your email. Nothing else. I do not sell it, and I will not send you anything except this race changing. One click gets you out.

I keep this catalog because the information is scattered and hard to trust. Telling you when it moves is the same job.