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Registration Info


Registration is currently closed. Stay tuned for 2020 dates!


First Come/First Served

We are no longer using the lottery system. Be ready to sign up when registration opens!


350 Person Racer Limit

We are expecting another great racer turnout for this year’s race so note that we have a racer cap of 350 total racers. We are dividing race numbers between the three races: 125 100-mile racers, 125 50-mile racers, and 100 Sorini 25-mile racers. However, if the 50 mile race fills up sooner than the 100 mile race, we will transfer the remaining 100 mile slots to the 50 mile on the date listed on the race schedule. Per Race rules, previous year’s overall podium finishers are offered preregistration.


Waiting List

The waiting list is first come first served. Those racers unsuccessful in gaining initial entry will be automatically entered into the waiting list. When a slot opens up for a waitlist registrant, you have two days to complete your registration before you are removed. Racers will be contacted by email as openings are reported.



Registration fees for The Butte 100 Races are NON-REFUNDABLE. This includes each race distance. The Butte 100, 50, & Sorini 25.



All races are non-transferable. between individuals & between race distances. Race entries are not transferable from one person/participant to another person/participant. Sale, trade and/or transfer of Butte 100 race registration is strictly prohibited and will result in the disqualification of offenders from participating at future Butte 100 Races. Anyone caught attempting to sell or transfer their race registration to another person/participant, will have said registration canceled and/or revoked, be disqualified, and be removed from the race without refund.



If you can’t race after registering, you have the opportunity to defer your race registration for the next year for a $20 dollar deferral fee. Deferrals will not be accepted within 35 days of the event. Please note: if you choose to defer to the Butte 100 or Butte 50 up from Sorini 25 or up from 50 to 100 race you will have to pay the difference in race fees. You will not receive a refund if you defer to a lower cost event from a higher cost event. Also, in the event that race fees increase in 2019, you may have to pay the difference from the previous year to current year. Your deferral can only be used for the following year. You will have the opportunity to register early the following race year. However, if you wait past the window of early registration and the race fills, then you will have to use your deferral on the waitlist and will not be guaranteed entry.

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