Cucumber Gulch is a 52-acre preserve of beaver ponds, willow carrs, and rare fen wetlands at about 9,800 feet, sitting between the Peak 7/8 ski base and downtown Breckenridge. It shelters moose, elk, mule deer, beaver, mountain lion, and more than 47 bird species, and it is one of Colorado's known habitat and reintroduction sites for the state-endangered boreal toad. The beaver dam complex regulates water flowing toward the Blue River.

A boardwalk-and-trail network off Ski Hill Road lets you watch the wetlands without entering sensitive ground, and the free BreckConnect Gondola passes an overlook above the ponds. Dogs are prohibited year-round, and some trails close seasonally for spring amphibian breeding and elk calving — the town manages this place for wildlife first, recreation second.

In winter, the gulch's edges carry Breckenridge Nordic Center groomed trails; a pass is required on groomed terrain.