The Royal Gore fire in Fremont County swelled to 3,800 acres, narrowly missed the iconic suspension bridge there and put western Cañon City, including state prisons, on alert, authorities said.
At 10 p.m., the Department of Corrections began evacuating about 800 inmates from the Colorado Territorial Correctional Facility in Cañon City to other local prisons, based on security levels and medical needs.
Department spokeswoman Adrienne Jacobson said the prisoners were being moved as a precaution.
The fire began Tuesday afternoon and the cause is under investigation.
The blaze consumed three structures, including at least one near the Royal Gorge Bridge and Park, where 1,400 guests and 200 staff members were evacuated.
"The last I heard from our fire managers is the bridge is still intact," fire information office Gregg Goodland said at about 8:15 p.m.
About 100 homes in the area were evacuated, he said.
An evacuation center was set up at the Evangelical Free Church in Cañon City.
About 150 local firefighters were battling the blaze Tuesday night, and state crews and equipment would be asked to join the fight Wednesday, Goodland said.
"The concerns firefighters have right now are weather-related," Goodland said.
While temperatures are expected to cool slightly on Wednesday, high winds could cause trouble for firefighters on Thursday, he said.
All of southern Colorado and the Front Range were under a critical "red flag" fire danger warning Tuesday.