The hatchery receives water from the South Fork of the Coeur d'Alene River and the Little North Fork of the Coeur d'Alene River. Two (6 ft x 65 ft) concrete raceways, as well as one (12 ft x 65 ft) concrete raceway and three dirt ponds approximately (30 ft x 100 ft), are used to hold fish prior to stocking to the Coeur d'Alene and St. Joe river drainages. One dirt pond has been developed as a show pond complete with a visitor's access deck, information board, and a feed dispenser.
The Mullan facility plays a vital role in supporting the put-and-take rainbow trout fishery. From this location, daily trips are made onto the Coeur d'Alene and St. Joe rivers, from May to September, providing the frequent stocking service needed to support such a fishery.The hatchery maintains a covered visitor information center with a map of stocking areas and information about the special harvest regulations in the Coeur d'Alene River and St. Joe River drainage.