This isn’t one of the most popular trails at Rocky Mountain National Park. It isn’t one of the longest, or most difficult. It doesn’t even have its own trailhead; instead, it starts off one trail and ends when it picks up another. But Boulder Brook Trail shouldn’t be missed.  The brook for which it is named is a bold splash of water that cascades down the mountainside over and under boulders. The trail follows the brook for just about two miles, crossing it five times on log bridges. At its upper reaches, the trail takes off across a sun-drenched hillside, sparsely dotted wit subalpine fir and wildflowers.

To get there: From Estes Park, take U.S. Highway 36 into Rocky Mountain National Park; turn onto Bear Lake Road and drive to Sprague Lake. Park there.

Hike: Start at the trailhead kiosk at Sorague Lake, and head up the Storm Pass Trail. This is a horse trail used by the Sprague Lake Stables. For about a half-mile, you’ll be dodging horse apples, waving off the accompanying flies, and trying you find your footing in a trailbed that has been badly eroded by the hooves of many horses. Many hikers are discouraged by the state of this trail, but those who walk on to the junction with Boulder Brook aren’t disappointed. The trails are well-signed. Watch for Boulder Brook, and begin your climb uphill. This is a steep, narrow trail, carpeted with round, softball-sized rocks. The trail is steepest at the bottom. head uphill, with the brook on your left. It’s deeply shaded here. About a mile and several creek crossings later, the trail levels out. Pass through some dense willows and climb again, more gradually. Soon, you’ll find yourself in an open area with an unobstructed view of Longs Peak ahead. Vegetation here has come back after a fire in 1900. Tree trunks, now gray and smooth, are still strewn about.  When the trail winds back into the forest and heads more steeply uphill again, you’re near the junction with Longs Peak Trail.

Details: $15 park entrance fee (per car; good for one week). Not handicapped accessible; dogs and bikes aren’t allowed. Picnic tables, grills, bathrooms with running water at Sprague Lake.

Trip Log: 2.5 miles.