The Britania Mountain Fire west of Wheatland grew to 24,105 acres as of Wednesday afternoon.
The fire was active primarily on the southern and southeastern flanks, prompting new evacuations in the Palmer Canyon area.
Rocky Mountain Incident Management Team Black assumed command of the fire at 6 a.m. Thursday morning.
Aviation resources were used to assist firefighters working on the ground Wednesday with both single engine air tankers and water drops from helicopters to slow the forward spread of the fire as well as help firefighters hold roads being used as fire lines.
Thursday, firefighters were continuing to construct lines and monitor established control lines on the fire.
As of Thursday afternoon, Rocky Mountain Team Black reported 368 personnel were assigned to the fire, with around 33% containment.