Old Dillon Reservoir is a small historic reservoir perched on a hillside above the town of Dillon in Summit County, Colorado, offering one of the most accessible and rewarding short hikes in the county. Originally built in the 1930s to supply water to the original town of Dillon -- now submerged beneath Lake Dillon -- this quiet body of water has become a beloved destination for hikers, dog walkers, and photographers drawn to its sweeping mountain panoramas. With a 4.8-star rating and thousands of trail reviews, Old Dillon Reservoir consistently ranks among the top easy hikes in Summit County.
The Old Dillon Reservoir Trail is a 1.6-mile loop that takes about 40 minutes to complete. The route climbs gently through aspen groves before emerging at the reservoir, where the views open up dramatically. To the southwest, the Tenmile Range dominates the skyline. Bald Mountain and Mt. Guyot rise to the south. From the north shore, you can see Silverthorne spread below with Buffalo Mountain and Ptarmigan Peak as a backdrop. Visitors describe the overlook as one of the best photo spots in Summit County, and the trail sees repeat visitors who bring different friends each time.
This is a family-friendly trail in every sense. Parents with young children, dog owners, and casual walkers all find it accessible and enjoyable. Dogs are welcome on leash, and the trail's gentle grade makes it manageable for hikers of all fitness levels. The relatively short distance means you can fit this hike into a morning or afternoon without committing to a full-day outing, making it a popular add-on to a day in Dillon, Silverthorne, or Frisco.
Fall is the standout season at Old Dillon Reservoir. The aspen-lined trail erupts in bright gold during September, drawing hikers and photographers from across the Front Range. Summer offers comfortable temperatures and long daylight hours, while spring brings wildflowers once the snow melts. The trail is accessible from roughly May through October, though early and late season visits may encounter muddy or snowy sections.
The trailhead is located off Dillon Dam Road, about 0.7 miles from Highway 9 in Dillon. A small parking lot serves the trailhead, and spaces fill quickly on summer weekends and fall foliage days. For the best experience, arrive early in the morning or visit on a weekday. The reservoir itself is not stocked for fishing and swimming is not permitted, as it was historically a water supply. The draw here is the trail, the views, and the chance to enjoy a quiet pocket of alpine beauty just minutes from Summit County's busiest towns.