The U.S. Forest Service says about 250 firefighters are working to contain the Fern Lake Fire, which has been burning for nearly two months.
The fire has scorched about six square miles.
Fire has burned at least one cabin and forced the evacuation of several areas in and around the park.
Larimer County Sheriff Justin Smith says some residents may be allowed to return on Wednesday.
(Copyright 2012 by The Associated Press. All Rights Reserved.)