Deering Reservoir is a 323-acre (1.3 km²)^[1] water body located in Hillsborough County in southern New Hampshire, United States, in the town of Deering. The lake serves as the headwaters to the Piscataquog River, which flows east to the Merrimack River in Manchester.

Deering Reservoir
Deering Reservoir Show map of New Hampshire Deering Reservoir Show map of the United States
Location	Hillsborough County, New Hampshire
Coordinates	43°03′33″N 71°50′47″W / 43.05917°N 71.84639°W / 43.05917; -71.84639
Primary outflows	Piscataquog River
Basin countries	United States
Max. length	1.5 mi (2.4 km)
Max. width	0.8 mi (1.3 km)
Surface area	323 acres (1.3 km2)
Average depth	11 ft (3.4 m)
Max. depth	37 ft (11 m)
Surface elevation	913 ft (278 m)
Settlements	Deering

The lake is classified as a warmwater fishery, with observed species including rainbow trout, smallmouth bass, largemouth bass, white perch, horned pout, and chain pickerel.^[1]