|Location||Strafford County, New Hampshire|
|Primary outflows||Bellamy River|
|Basin countries||United States|
|Max. length||2.2 mi (3.5 km)|
|Max. width||0.7 mi (1.1 km)|
|Surface area||341 acres (1.38 km2)|
|Average depth||9 ft (2.7 m)|
|Max. depth||25 ft (7.6 m)|
|Surface elevation||279 ft (85 m)|
Swains Lake (also known as Union Lake) is a 341-acre (1.38 km2) water body located in Strafford County in eastern New Hampshire, United States, in the town of Barrington. Water from Swains Lake flows via the Bellamy River to the Piscataqua River estuary. A boat launch is available off Young Road. During the spring and summer it is a popular boating destination, while the ice of the colder months connects several snowmobile paths.
- U.S. Geological Survey Geographic Names Information System: Swains Lake
- U.S. Geological Survey Geographic Names Information System: Union Lake
- "Swains Lake, Barrington" (PDF). NH Fish & Game. Retrieved September 5, 2014.