Black Sandy State Park, State park on Hauser Lake in Montana, US

Black Sandy State Park is a state park with over 40 acres of shoreline on Hauser Lake northeast of Helena, providing camping and water recreation. The facility includes both electrical and basic campsites to suit different visitor needs.

The land was originally managed by a utility company and transferred to the state wildlife department in 1980 as public recreation space. This handover converted the shoreline into an accessible destination for the region.

The park lies along the Lewis and Clark National Historic Trail, the route of the 1804–1806 expedition. A visitor can follow the shoreline where the trail passes the western shore of Hauser Lake.

The park is easily accessible by car with parking available near the campsites and facilities. Water conditions are best during warmer months when the lake is fully open for swimming and fishing.

The park lies at 1,181 metres on the western shore of Hauser Lake, a Missouri River reservoir. Anglers catch rainbow and brown trout, walleye and perch. Just south, the BLM's White Sandy Recreation Area adds campsites. In 2012 a $40,000 concrete office was proposed to replace the wooden 8-by-12-foot building.