Foss State Park is a 1,749-acre (708 ha) Oklahoma state park located on Foss Lake, in southwestern Custer County, Oklahoma, near the city of Foss.Recreational activities include hiking, biking, horseback riding, fishing, boating, swimming and camping. Facilities include 110 RV campsites, 10 of which have full-hookups and 100 that are semi-modern. All sites are paved and offer 30 amp or 50 amp service plus water. Big rig sites, shaded sites and 35 tent sites are also available.