Potholes Reservoir is a 28,000-acre body of water located approximately seven miles south of Moses Lake in Grant County, Washington. Built behind O'Sullivan Dam (the longest earthen dam in the country), this diverse fishery is known for its unique network of sand dunes, channels, islands, and underwater structures that create exceptional habitat for numerous fish species. The reservoir is fed by Crab Creek, which flows out of Moses Lake, and features distinct northern and southern sections with different fishing characteristics. Open year-round, Potholes offers excellent fishing for both warm-water species and trout, making it one of the premier multi-species fisheries in the Pacific Northwest.