Foss Lake, the largest body of water in Oklahoma, has an 8,800-acre surface area, a 63-mile shoreline and lies just north of Foss and west of Clinton. The lake was constructed after the Washita River was dammed in 1958 to create a water storage area.
Foss Lake along with the surrounding land is known as Foss State Park, an area that includes the Washita National Wildlife Refuge and Lake View Recreation Area. Foss State Park boasts more than 130 campsites as of 2015, a marina, a swimming beach and boat ramps. Visitors can go boating, water skiing or fishing on the lake or explore the state park's many trails. The 17-mile Warrior Trail meanders along the lake, making a good hiking and horseback riding path. Foss Lake is also the site of the annual Christmas in July festival featuring fireworks, boat parade, lighted camper contest and jet ski scavenger hunts.
Foss Lake is also the site of two long unsolved cold cases. In 2013, two separate cars were found in the lake containing six bodies total dating back to 1960 and 1970. The identified bodies belonged to six people missing for more than 40 years in what police believe was an accidental plunge into the lake.