Challenge yourself to run the Boulder Skyline!

The Boulder Skyline is a classic run/hike of the Boulder area. It connects Boulder’s five highest summits connecting some of its most iconic trails. Whether you’ve never run the skyline or you’ve run it a hundred times, this challenge is for you.

The challenge is to run the Boulder Skyline Traverse as many times as you can from the Fall Equinox (September 22, 2020) to the Winter Solstice (December 21, 2020).

Entry is cheap and goes to a good cause. I’ll validate all runs and keep a leaderboard on this website. I’ll also setup a Facebook page so we can share pictures and experiences with each other.

I hope y’all will join me, your friends, and fellow Boulderites in pushing ourselves on one of the best local trail routes.



The route can be run in either a Northbound or Southbound direction. In a single-segment run/hike, you must summit the following peaks (Northbound order): South Boulder Peak, Bear Peak, Green Mountain, Flagstaff Mountain, and Mount Sanitas.

Any combination of trails that summits these 5 peaks qualifies as a Skyline Traverse. To compete on time, however, you must run the “official Fastest Known Time” route, starting and ending at South Mesa Trailhead and Mount Sanitas Trailhead. Please refer to the link below for specific route information.

If this is your first time running or hiking the route, I highly encourage the Northbound official route. If you’ve done it a bunch of times, try going up Fern canyon and double-summitting Bear, or challenge yourself by adding Anemone hill. And, if you really want to challenge yourself, the Double Skyline Traverse 50K is always an option (It counts as two, but be sure to double the entire route!).

For hikers, the Skyline will take 7-10 hours. For runners, it will take 4-6. Add more time if it recently snowed, as the backside trails are less packed. Water is available at Eben G. Fine park between Flagstaff and Sanitas. Non-potable water (treat or filter your water!) is usually found in Bear Creek between Bear and Green.

Note that both Bear Peak’s and Flagstaff Mountain’s true summits are off-trail. For Flagstaff, it is sufficient to get to the high point of the Ute trail, where the 4-way trail intersection is, near the summit area. And for Bear, it is sufficient to reach the summit pole just shy of the scramble.

SAFETY: The Skyline Traverse is hard. Do not underestimate how long it will take. Check the weather before you go out. Bring a rain jacket just in case. Bring enough water. Go with experienced runners/hikers if you are unsure. If you ever feel unsafe, you can exit the couse at many points by descending to the East (towards Boulder).


To enter, you must donate $10 (or more!) to the Boulder Area Trails Coalition (BATCO) in support of the Trail Around Boulder.

Then forward me ( your PayPal receipt to register. Please put “Skyline Challenge” in the subject line! Also make sure the email includes your name, gender (M/F/NB), and preferred email (if different than the one you forward from).

What do you get for your entry? A sticker! That’s right. In addition to all the warm fuzzies you’ll get from donating to help build and maintain local trails, you’ll also receive a Boulder Skyline Traverse sticker designed by local artist Anthony Cozzi. Sticker’s will be ordered from local printer StickerGiant. Distribution will be handled in a later email.

Submitting Results

Submit your results

Please submit your runs within 5 days of running them. Please record your runs/hikes on your phone or GPS watch, and upload your runs/hikes to Strava, MapMyRun, Garmin, etc, and make your runs publicly accessible. Raw GPX files will not be accepted. All submissions are subject to validation. Submissions can be emailed to me (subject: Skyline Challenge) or by using the form linked above.

Who is the Organizer?

I’m Jon “Cowboy” Eisen. I’ve lived in Boulder for six and a half years. Boulder has changed my life. When I moved here, I lived a very sedentary life. Joining the Boulder running community helped me transform myself into a happier and more athletic person. I now run weekly with local trail groups and participate in ultramarathons.

I’m organizing this challenge to give the Boulder running community something to challenge ourselves on during this tough season with so many race cancellations and tough times. This is my first time doing something like this.

By entering this challenge, you assume all personal risk, including the risk of running or hiking the Boulder Skyline Traverse trail. As I am not receiving any money, and there is no gathering of challengers. This event is unpermitted. Please follow all OSMP, Boulder City, Boulder County, and Colorado State regulations when attempting the Boulder Skyline Traverse. This includes: WEAR A MASK, don’t run in large groups, and practice good trail etiquette.

Privacy Policy: I will collect your name, email, gender, amount donated to BATCO, and information pertaining to the runs you submit to me. I will keep this information in case we continue this challenge yearly to be able to look at growth. I will share with the public the following information on the leaderboard: name, gender, total everyone has donated to BATCO, and statistics and information about the runs you submit to me. I will NOT share your email or the amount you donated. If you wish to be kept completely anonymous, notify me when you send your registration email, and I will not release any of your information to the public. If at a later date, I need your address for sending you something, I will not keep that information.