iTR Race Series
Embrace the adventure with one or all of our Inside Trail Racing Series! Find your trail challenge, whether it's conquering a long run, cultivating consistency, or savoring the joy of the trails with us! Join the Inside Trail Racing Series for some fun!
Sub-Ultra Series
Join us for a series of shorter races. We will add up the points for those who run iTR event distances between 25k and 35k and conclude with a season winner.
Inside Trail Racing Series has 17 Sub-Ultra races throughout the year. You must participate in at least 6 events to be eligible for the Sub-Ultra Series. Your Top 6 scores will be counted.
Craft Sportswear
Craft Sportswear is our presenting sponsor for the Sub-Ultra Series in 2026!
SCORING
The series scoring system will be based on points calculated based on place, race distance, and runner’s performance.
Each runner in every race will start with a base score of the distance run (in miles) multiplied by two. This number will then be multiplied by the result of the race winner’s time (in seconds) and then be divided by the runner’s time (in seconds).
Score = ((Distance in Miles x 2) x Winner’s Time in Seconds) / Runner’s Time in Seconds
PRIZES
Our sponsors will donate the prizes. Men’s and Women’s awards and prizes will be three deep.
Grand Prize:Â 5 Free ITR Entries, ITR Hat or Visor, a pair of Craft shoes!
Runner Up:Â 3 Free ITR Entries, ITR Hat or Visor, a pair of Craft shoes!
Second Runner-Up:Â 1 Free ITR Entry, ITR Hat or Visor, a pair of Craft shoes!
iTR Race Credit will be added directly to UltraSignup. Credit is NOT redeemable for cash and must be used within 12 months of earning it.
The 50/50 Challenge
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Our 50/50 Challenge includes our two 50-milers: Monterey Ultra 50M and Marin Ultra Challenge 50M. They are 100.9 miles and 17,000’+ elevation gain, FIVE weeks apart.
You can register for the 50/50 Challenge in the Monterey Ultra 50 Miler registration for a discount or sign-up for both individually. Once Monterey Ultra has passed, the discount is no longer available.
Scoring
For 2026, Winners will be identified by the fastest combined time between the two events.
Prizes
100% iTR Race Credit to the overall winners (Female & Male)
50% iTR Race Credit for 2nd Place overall
25% iTR Race Credit for 3rd Place overall.
iTR Race Credit will be added directly to UltraSignup. Credit is NOT redeemable for cash and must be used within 12 months of earning it. You can sign up for the challenge in UltraSignup under the Monterey Ultra registration, or if you want to separate the registration fees, you can register for each individually and indicate in Marin Ultra Challenge that you are completing the 50/50 Challenge.
Fall 50K Cup
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Run THREE out of FOUR end of the year 50K’s to qualify for iTR’s Fall 50K Cup! ALL Participants will earn a 50K Cup coffee mug, and we’ll be dishing out iTR UltraSignup race credits to the winners! You must run three of four 50 K’s: Rodeo Valley (August), Berkeley Trail Adventure (September), Mt. Tam (November) & Woodside Ramble (December)
Presenting Sponsor 2026Â
TBD
Scoring
The winner of a race receives 100 points. Every other racer receives points based on their time compared to the winner’s.
It is calculated by dividing the winner’s time (46 minutes) by the participants (62 minutes) and multiplying the results by 100. So 46/62 x 100 = 74.2
Points are calculated separately for men and women racers. Men use the men’s winning time, and women use the women’s winning time to calculate points.
Your total score is the sum of all race scores.
Prizes
Female Overall – 100% Race Credit + iTR Trucker Hat or Apparel Item + Sponsor Item
Male Overall – 100% Race Credit + iTR Trucker Hat or Apparel Item + Sponsor Item
Female & Male Age Group Winners – 50% Race Credit
iTR Race Credit will be added directly to UltraSignup. Credit is NOT redeemable for cash and must be used within 12 months of earning it.
Notice for all iTR Race Series Events
*** Prizes, races, & race dates are subject to change ***
*** Management reserves the right to disqualify runners who violate rules and/or waivers at any race ***
