The Marin Ultra Challenge, our premier Marin County long distance trail race, delivers ample hills and sweeping descents. 2025 marks the 12th 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 back pack! When signing-up for Monterey Ultra 50 Miler you will be able to register for the 50/50 Challenge!

Event Schedule:

50 Mile - 6:00 AM

50K - 7:00 AM

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.

Click Here For Registration: