Before we give you a list of states whose ccw permits are honored by Colorado there is some things you need to know.
First, that regardless of the laws of the state where the permit was issued, Colorado will not honor a permit in the hands of anyone under the age of 21. Also Colorado only honors permits issued to residents of the state issuing the permit. In other words, a Utah permit in the hands of a Wyoming resident will NOT be honored in the state of Colorado, even though Utah is listed as a state who shares reciprocity with Colorado.
To get the most up to date list of states, whose permits are honored by Colorado, visit this website.