Aspen Center for Environmental Studies

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Aspen Center for Environmental Studies

A short walk from the bustling upscale shops of South Mill Street sits the quiet Aspen Center for Environmental Studies, in the 22-acre Hallam Lake Nature Preserve. ACES is a perfect place to relax, take a hike or learn about native plants and animals. Read More

  • 100 Puppy Smith St., off Mill Street in Aspen
  • Entrance is free
  • 9 a.m. to 5 p.m. Monday through Saturday in Summer
  • Other seasons: 9 a.m. to 4:30 p.m. Monday through Friday


This family-friendly environmental center is an ideal sojourn for those who are outdoor-curious but backcountry shy, as it offers a perfect introduction to the great outdoors. Numerous natural science programs are offered throughout the year, and the center is renowned for its work with school-age children It also has activities for all generations and interests.

A self-guided nature trail snakes around the preserve and is a favorite with bird-watchers. Deer, foxes, beavers and bears also frequent the area. The visitor center features an indoor trout stream swarming with native cutthroats, as well as an environmental library and a gift shop full of books, gifts and toys. The center rehabilitates birds of prey, and often visitors can interact with great horned owls or golden eagles.

On-site naturalists provide information about nature and wildlife and give tours of the nature preserve year-round. In the summer, ACES offers naturalist-guided walks; birds of prey demonstrations; children's programs; sunset beaver walks; and interpretive campground programs. In the winter, naturalists lead snowshoe hikes at various locations, including the top of Aspen Mountain.


ACES is located in the Hallam Lake Nature Preserve. From Main Street in Aspen, go north on Mill Street, take a left on Puppy Smith Street and go past the post office. The road dead-ends at the Aspen Center for Environmental Studies. Park on the left and walk down the driveway.


Sumer hours: 9 a.m. to 5 p.m. Monday-Saturday; other seasons: 9 a.m. to 4:40 p.m. Monday through Friday


Entrance is free. Cost for tours and programs varies