The Tom Blake Trail, Anaerobic Nightmare Trail and Government Trail 1980, all in the Snowmass area, are closed until June 21 to protect elk-calving habitat.
Cow elk are hungry after the long winter and need a quiet place to nurse their young.
They return to the area between Two Creeks and West Buttermilk because it offers water and food.
Interaction with humans can stress elk and, in some cases, lead them to abandon their calves.
Violating this closure can result in fines between $50 and $5,000.