Explore with us this summer

Upcoming Activities

Activities at ACES


Monday, June 17


ACES Educator-in-Training Volunteer

Weekly, M-F

Monday, June 17


ACES Summer Camp 2024


Sunday, July 14


River Run Sunset Hike

ACES’ mission is educating for environmental responsibility.

Aspen Center for Environmental Studies (ACES) is a nonprofit environmental science education organization. ACES has worked since 1968 to inspire a life-long commitment to the earth by providing immersive programming for all ages. Our programs focus on ecological literacy, regenerative agriculture, forest and ecosystem health, land restoration, and environmental leadership.

Our Locations

Rock Bottom Ranch

Wednesday-Friday 9am-4pm, Saturdays 9am-1pm

Rock Bottom Ranch

Rock Bottom Ranch serves as ACES' mid-valley hub for environmental education, wildlands preservation, and sustainable agriculture. The 113-acre wildlife preserve and educational Ranch sits between the Roaring Fork River and the Crown of Mount Sopris and is conveniently located…

Hallam Lake

Mon - Fri, 9am-5pm
Sat, 9am-5pm in summer

Hallam Lake

Hallam Lake, a 25-acre nature preserve and environmental learning center, was the first location of the Aspen Center for Environmental Studies. The Hallam Lake property was donated in 1968 by Elizabeth Paepcke. The preserve is open to the public year-round and provides an inspiring...

Catto Center at Toklat

Closed for renovations until spring 2023

Catto Center at Toklat

The Catto Center at Toklat was once the family home of one of ACES’ most influential founders, Stuart Mace, and holds great meaning for the Aspen community. Toklat, an Inuit word meaning “headwaters,” was built by Stuart and and his wife Isabel in 1948 as a wilderness lodge and family...

Read the Blog

Working together we can make a difference.

Protect our world for the future. A donation to ACES allows us to forge bold innovation in environmental science education, ecological literacy, forest health, restoration of our lands, and sustainable agriculture. We hope you will make an investment in nature today and join a community of environmental stewards!