Boulder Skyline Traverse

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March 16, 2026

Directly bordering the west side of Boulder, Colorado are five peaks that make up the western skyline which are visible from most of the city. The Boulder Skyline Traverse is a popular way to link them. The route consists of all trails which never stray that far from the city itself, making it a great way to spend a few hours of cardio time. Most people do the route as a point-to-point with a car shuttle, starting at South Mesa Trailhead and ending at Centennial trailhead. For those unable to car shuttle, a bike is also an excellent choice to cross back through the 9.5-mile distance between trailheads. 

Peaks climbed

Peak	Elevation	Topographic Prominence	Summit Coordinates (lat/lon)
South Boulder Peak	8,541 ft	1,097 ft	39.95371, -105.29932
Bear Peak	8,460 ft	290 ft	39.96021, -105.29514
Green Mountain	8,136 ft	525 ft	39.98214, -105.30156
Flagstaff Mountain	7,000 ft	246 ft	40.00152, -105.30727
Mt. Sanitas	6,800 ft	40 ft	40.03432, -105.30523

Total Stats

17.2 miles

5,800/5,900 ft gain/loss

Brent and I met at Centennial shortly after sunrise, taking about 20 minutes to drive to South Mesa. It was a cold brisk morning with temperatures around 16F. We had initially hoped to go climbing, but it had snowed the previous night. We were happy with this decision as we passed several snow coated crags on the way up South Boulder Peak. 

We took the Mesa Trail for about 1.5 miles before turning west on a smaller rocky trail which headed steeply up Shadow Canyon which was a serene scene with the snow-covered trees and rocks. As we hit the saddle north of South Boulder Peak, we were buffeted by strong northwest winds which probably dropped the wind chill into the negatives. A short out-and-back ascent to South Boulder Peak ensued. Excellent views were had to the south looking towards the peaks of the Scar Top Traverse. 

Continuing north from the saddle, we tagged the summit of Bear Peak which required a shorter out-and-back from the main trail. This peak had the best views of the day, with unobstructed views towards Boulder and the Flatirons. 

A quick snowy descent on a rocky trail down the northwest ridge of Bear Peak quickly eased up and was soon replaced by smooth gradual switchbacks heading up the west side of Green Mountain. These trails were super runnable. A quick 10-minute out-and-back was required to summit Green Mountain. The views here were mainly blocked by trees. 

Another trail dropped us down the north ridge of Green Mountain and and into Long Canyon where we crossed Flagstaff Rd. A network of spider web trails brought us up the south ridge of Flagstaff Mountain which was crowned by a 6 ft block in the middle of a field. 

From Flagstaff, a series of trails headed east and then north, crisscrossing Flastaff Rd multiple times. It would've been easy to just zone out and take the wrong trail here as there seemed to be hundreds of them in multiple directions. 

Eventually we made our way down to Boulder Canyon, where we stopped at a park and filtered some water out of Boulder Creek. A trail tunnel then brought us under Boulder Canyon Dr which we crossed through and then ascended and descended a small rise to drop to Centennial Trailhead where the other car was located. We weren't done yet, as there was still one remaining peak to the north, so we walked right past the car and north up the Mt. Sanitas Trail which pretty much stayed in line with the south ridge of Mt. Sanitas. This was a rocky steep trail that was popular with locals in Boulder for their workout routines. 

In no time we were standing on the summit of Mt. Sanitas, which was merely a lower sub-peak of a higher peak just a few hundred feet to the north. It did have good views of the city though. 

To change things up, we decided to make a loop of Sanitas rather than going back down the south ridge. We headed down the East Ridge Trail and then took the Sanitas Valley Trail back to Centennial, which both of us would recommend doing.