According to Cpr.org:
On Friday, April 2, Gov. Jared Polis announced by executive order that nearly half of Colorado's counties will be freed from the state's comprehensive mask mandate, based on low enough COVID incidence levels.
The order, which remains in effect for 30 days, releases counties now at level "green" on the state's color-coded COVID-19 restrictions dial from the statewide mask mandate. Those counties will still have the authority to set their own mask restrictions should they choose.
As of April 12, 34 counties in Colorado are listed as level "green" on the state's COVID dial, which means the county no longer has to abide by the state's mask mandate. Those counties are:
Alamosa
Baca
Bent
Cheyenne
Costilla
Conejos
Crowley
Custer
Delta
Dolores
Gilpin
Gunnison
Hinsdale
Huerfano
Jackson
Kiowa
Kit Carson
Lincoln
Logan
Mineral
Moffat
Montrose
Ouray
Otero
Park
Phillips
Prowers
Rio Blanco
Rio Grande
Saguache
San Juan
Sedgwick
Washington
Yuma