Trustom Pond is a closed lagoon in South Kingstown, Washington County, Rhode Island, United States. It is one of nine coastal lagoons (referred to as "salt ponds" by locals) in southern Rhode Island. It has a surface area of 800 acres (320 ha), and is the only undeveloped salt pond in the state. The pond averages 1.3 feet (0.40 m) deep, and has a salinity level of 5 parts per thousand. It is non-tidal, except when breached by storms. The water directly receives about 219,844,022 US gallons (832,200,150 L) of precipitation per year, with an estimated 796,215 US gallons (3,014,000 L) in daily groundwater flow.