Sarge's Compound is a small portion of Carburetor County, owned by Sarge. It can be entered by turning right near the entrance to Tailfin Pass, where a bridge will eventually lead into Willy's Butte. Sarge's Boot Camp is considered part of it.
In Cars: The Video Game, it is open during exploration mode. It is used during most of Sarge's races.
In Cars: Mater-National Championship, it is for some reason closed and can now only be entered through Sarge's races and a few minigames.
In Cars: Race-O-Rama, it is now open again.