Trail Run Project Logo

Chicago Basin 14er Grand Slam

Extremely Difficult


28.9 mile 46.5 kilometer out and back
63% Runnable
Extremely Difficult


Ascent: 12,167' 3,708 m
Descent: -12,167' -3,708 m
High: 13,935' 4,247 m
Low: 8,198' 2,499 m


Avg Grade: 16% (9°)
Max Grade: 68% (34°)


Driving directions Take a virtual tour
Zoom in to see details
Map Key

Trail shared by Tyler Prince

An epic day covering all four of Chicago Basin's challenging 14ers.

Tyler Prince

Features Fall Colors · Lake · River/Creek · Swimming · Views · Waterfall · Wildflowers · Wildlife

This run must be accessed via the Chicago Basin Trail, which is in turn accessed either by train (summer only) or by a long run in (Animas River Trail).

While portions of this run can easily be explored by fit dogs, the peaks above it are generally too technical for them.

Camping high in the basin is generally frowned upon. See Twin Lakes Approach for further information; camping along the end of Chicago Basin Trail is preferred.


This truly epic run summits all four Chicago Basin 14ers in one fell swoop. While seemingly short and with surprisingly little vertical, runners should know that all of these peaks are at least somewhat technical, and this day is sure to exhaust everyone short of Ueli Steck. Starting at camp, it takes runners up the Twin Lakes Approach, up Sunlight and Windom, back down and over to the Eolus Group, and finally back down Twin Lakes Approach. Between 14er finishers, completing all these mountains in one day is a big deal, and offers some pretty awesome bragging rights.

Need to Know

While similar in distance and elevation gain to many Sawatch 14ers or to 14er quadruple DeCaliBron, this run is a whole other beast.

Runner Notes

This is a mixed bag of terrain, better for hiking fast than for truly running. Twin Lakes Approach is absurdly steep and in some parts rocky, but largely runnable. Sunlight and Windom are rocky and technical, and basically impossible to run. The Eolus Group's lower trail is very runnable, for about 2 miles, before reaching the more technical upper portions. Overall, this isn't a bad trip for a runner who's open to some technical scrambling and slower hiking for much of the journey.


This is a hell of a trip. From camp off the Chicago Basin Trail:

Run up Twin Lakes Approach. From here, it's recommended you summit Sunlight and Windom first, as the rock on Sunlight is slightly more technical and prone to getting slippery. It's easier to escape from the Eolus Group should the weather change later in the day.

So, run Sunlight and Windom. Come back down to the Twin Lakes and run the Eolus Group. From here, all that's left is a descent back down Twin Lakes Approach.

Flora & Fauna

From world class alpine views and vegetation to unique alpine critters, Chicago Basin's got it all. Wildflowers down low are stunning. Marmots and pika are everywhere, and mountain goats love it up high, especially near Twin Lakes.

Run this trail?

We need help with the following missing trail information:

Dogs Allowed, History & Background

Is something wrong? Let us know. Have photos to share? Help fellow runners know what's here.


Rate This Run

Rate Quality

   Clear Rating

Rate Difficulty

Share This Run

Check In


Dec 14, 2015
Zach Roth
Along Animas - up to chicago basin - summit 14ers and back! 38mi

Trail Ratings

  5.0 from 4 votes


  5.0 from 4 votes
5 Star
4 Star
3 Star
2 Star
1 Star
Run Rankings


in Colorado


180 Views Last Month
16,270 Since Apr 16, 2015
Extremely Difficult



Sunrise from Windom Peak.
May 3, 2017 near Silverton, CO
Sunlight Spire and Windom Peak from Sunlight Peak. The last day of good weather.
Aug 3, 2018 near Silverton, CO
A view from above.
Apr 22, 2015 near Silverton, CO
Chicago Basin ~ San Juan Mountains, CO
Apr 22, 2015 near Silverton, CO
Here are some goats. They're everywhere, but mostly stay on the Eolus side of the Basin.
Apr 23, 2015 near Silverton, CO
A refreshing, albeit frigid, swim at Twin Lakes.
Apr 23, 2015 near Silverton, CO


Trail Run Project is part of the REI Co-op family,
where a life outdoors is a life well lived.

Shop REI Running