From the north: Take the Georgetown exit off of Interstate 70. Drive through Georgetown and follow the signs for the Guanella Pass Scenic Byway. Drive 12 miles to the top of Guanella Pass (11,700’) and park in one of the two large, paved parking areas on either side of the road. The Bierstadt trail starts near the parking area on the east side of the road. The upper parking area (on the west side of the pass) has restrooms.
From the south: Take US 285 west from Denver or east from Fairplay. Drive to the town of Grant which is about 12 miles west of Bailey. In Grant, turn north on the Guanella Pass Scenic Byway and drive approx. 13 miles to Guanella Pass.

Details:

From the top of Guanella Pass, find the trailhead near the restrooms in the upper parking lot (on the west side of the road) Photo #1. Do not follow the crowds, most people will be heading towards Mt. Bierstadt (on the east side of the road). Shortly after starting, a sign Photo #2 will direct you toward Square Top Mtn and Square Top Lake. Hike through the well marked trail over several wooden bridges - Photo #3. Mt. Bierstadt and Mt. Evans will be visible behind you for most of the trail - Photo #4.

You will come to a fork in the trail with a sign directing you to continue straight to Square Top Lakes in Photo #5. (Heading left will lead you to the Southeast Ridge - Class 1 climb; see other route here). The trail remains well marked for a little while longer - Photo #6, but will eventually end once you near Square Top Lakes. Photo #7 shows the trail near the end and shows the way up to the summit via the Northeast Ridge.

Approach the Square Top Lakes, and the trail will have disappeared - Photo #8. Ascend to the top of the ridge by heading northwest where the climb is not as steep. Photo #9 shows the view half-way up the ridge looking down. One you reach the top of the ridge, head southwest toward the summit. Photo #10 shows the terrain is not as easy and will require some scrambling at times. Continue up to the summit, but don’t be fooled by the false summits, such as in Photo #11. Photo #12 shows the view from the summit looking east and Photo #13 shows the view looking west.