Sun Lakes-Dry Falls State Park (formerly Sun Lakes State Park) is a 4,027-acre (1,630 ha) Washingtonstate park located near Coulee City at the foot of Dry Falls. Formed by the Missoula Floods, Dry Falls is the site of a former waterfall which is now a stark cliff, 400 feet (120 m) high and 3.5 miles (5.6 km) wide. When the floods occurred, the waterfall was ten times the size of Niagara Falls. Today it overlooks a desert oasis filled with lakes and abundant wildlife. It is a prime example of shrub-steppe habitat. There is an interpretive center on area geology. The park is located in Grant County, Washington along Route 17, at the head of the Lower Grand Coulee.
The park has 73,640 feet (22,450 m) of lake shoreline and offers fishing, swimming, boating, hiking, horse rentals, and a golf course. The campground includes access to the lake, a swimming pool, and a mini golf course. The park is also home to Camp Delany, with eight 9-person cabins and a central meeting hall accommodating up to 120 people.