Officials said late Thursday afternoon the fire should be controlled by evening.
The Spokane Fire, estimated at 5-10 acres, was reported about 10 a.m. It was fully contained about 90 minutes later, according to the Great Plains fire dispatch center in Rapid City.
Officials said the fire was burning in Custer State Park, around Iron Mountain Road and Playhouse Road.
There are homes in the area. Early Thursday afternoon, authorities said one structure was being protected but that it was not in immediate danger.
The fire dispatch center said two hand crews, 18 engines, three water tenders and other help was on the scene.
Kelly Stover of the Plains Information Center said officials worked Thursday to determine the cause of the fire and think human activity may be to blame. However, he said the cause remains under investigation.
Wind gusts of more than 60 mph were reported in the Rapid City area around 10 a.m.
