The 2020 Madison / Big Sky Double Half Marathon Weekend

Ennis, MT 59729, USA


  Thanks for your interest in the Greater Yellowstone Adventure Series (GYAS) races.  We have not cancelled the GYAS events for 2020.  However, we have temporarily closed our registration for all the races until the situation becomes more clear.  Montana is under Phase One of its opening which limits group sizes to no more than 10 people.  If the Governor decides to go to Phase Two, groups of up to 50 people will be allowed.  At that time, we will try to obtain race permits to allow some or all of our races to be held in a limited format as originally scheduled from July 16 to July 26.  There is no guarantee that we can obtain permits under Phase Two, but it’s our intent to try and do so.


Please sign up for our newsletter to keep in the loop on this situation.  Go to our race website – – and click on the newsletter ‘Stay in the Loop’ link to get on the mailing list.  Thank you.


Stay Happy, Healthy, and Always Keep Running Forward.


Sam Korsmoe

Race Director

Greater Yellowstone Adventure Series

 In the great state of Montana, there is only one place where you can do back to back half marathons (at least within one series).

We are it.

In the great nation of America, we are the only race series that offers a double half marathon consisting of One of The Highest Road Half Marathons on Planet Earth followed by The Second Longest Downhill Road Half Marathon on Planet Earth.

We used to be THE HIGHEST road marathon in the world (for sure, we're in the Top Five) and we're pretty sure only a Colorado marathon has us beat in the downhill road category (net drop).  

Whatever..... this is one awesome Bucket List double!

The Madison Half Marathon has an average elevation of more than 9,000 feet above sea level.

The Big Sky Half Marathon has a net drop of over 3,000 feet.

Oh, and we're right next to Yellowstone National Park. This makes us a superb vacation destination for marathon families. Come check us out this summer. This places doesn't disappoint.