The so-called Robbers Fire is burning in rugged terrain near the community of Colfax. The blaze is 30 percent contained.
Officials said 170 homes are threatened. The flames already destroyed one house and four outbuildings.
Since the blaze broke out last Wednesday, it has consumed nearly four square miles and left 12 firefighters injured.
Residents are evacuated from the Yankee Jims Canyon and Shirttail Canyon areas, as well as parts of Iowa Hill. The cause of the fire remains under investigation.
The Associated Press contributed to this report.