Firefighters are making "excellent progress" on a fire in northern Fremont County that has burned 22 acres, the U.S. Forest Service said in a news release Sunday.
"Regardless of the difficult terrain, significant line construction was accomplished," the agency said. "Aircraft assisted on the more active portion of the fire."
Dubbed the North Millsap fire, officials said the blaze started just after noon Thursday between Shelf Road and Phantom Canyon, about 11 miles north of Canon City.
The blaze was caused by a lightning strike, officials said. As of Sunday afternoon, it is at 20-percent containment.
No structures have been threatened, the Fremont County Sheriff's Office reported.
Officials said 70 personnel from several agencies - including the Bureau of Land Management and U.S. Forest Service in Colorado - and a helicopter are battling the fire.