Thank you to everyone who attended and participated in the 2021 GTIS Half! It was a GREAT day!!! For those folks who won an award, we will be giving out awards on Saturday, August 21st from 11am -1pm and Wednesday, August 25th from 5pm -7pm at Runner's Roost Lakewood at 7978 W Alameda Ave A, Lakewood, CO 80226. If you are not able to attend, please reach out to us to make arrangements to collect your award. For those of you who still need to collect your t-shirt and medal, please join us on Saturday at Runner's Roost Lakewood or stop by the store anytime during business hours through Wednesday, August 25, 2021.
***Race packets that are not collected by 8/25/21 will be mailed out.***

Georgetown to Idaho Springs Half

Saturday, August 14, 2021
Colorado at its Best! Run a PR at one of Colorado's oldest half marathons!
43rd Annual GTIS HALF
August 14, 2021
  • GTIS HALF MARATHON | Facebook Page
  • GTIS HALF MARATHON | Instagram


  • COVID MITIGATION: While there will be some changes to our traditional event due to COVID, one thing hasn't changed - the beautiful Colorado scenery! At this time, we anticipate facial coverings will be required in all areas of the event except for while on the race route. Participants will be expected to wear a mask up to the start line, once across the start line, it is at their discretion to remove their mask. We encourage participants to be respectful of those around them, most especially around our amazing volunteers that are out there supporting your efforts!

  • For the start line, this means small groups, socially distanced, will start every 15 minutes beginning at 7:00am. YOU get to select your start time during registration. These times will be strictly adhered to, please plan your arrival accordingly.

  • RUN PERKS: Custom finisher medal, great shirt, fresh mountain air, beautiful scenery, and a fun post-event celebration (on-the-go COVID style finish line celebration).

CO Mtn Half Series.jpg


Run Your Tranquility in 2021: Three of Colorado’s original and most beloved half marathons have teamed together to create the Colorado Half Mountain Marathon Series! Start the series with the Estes Park Half Marathon on 6/20/21, then run a PR at our very own GTIS Half on 8/14/21 and finish the series in Nederland at the Ned*Ned Half Marathon on 9/11/21. WE ARE ALL SOLD OUT FOR THE 2021 SERIES.


The Perks: Register for the series and save 15%. Participants will receive a custom designed medal from each event that combines to make one seriously Rocky Mountain High worthy medal. Overall and age group series awards and prizes and get discounted branded Colorado Mountain Half Series Gear. Learn more and sign-up at

 2021 IS SOLD OUT!




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