The Rockerville Volunteer Fire Department responded to a fire at The Gas Light restaurant around 10 p.m. on Sunday.
Due to the size of the fire, crews called for extra help. 21 agencies are now assisting with this fire.
The Rapid City Fire Department, Red Cross and other emergency service providers are on the scene.
Crews had the majority of the fire under control by 2 a.m.
Authorities say there are 43 fire units working to extinguish what is left of the fire.
The cause of fire is under investigation.