|Location||Plymouth and Bristol County, Massachusetts, U.S.|
|Coordinates||41°48′00″N 70°56′58″W / 41.80000°N 70.94944°WCoordinates: 41°48′00″N 70°56′58″W / 41.80000°N 70.94944°W|
|Type||Natural freshwater lake|
|Primary inflows||Stream fed from marshes|
|Primary outflows||Long Pond River, aka Snake River|
|Basin countries||United States|
|Max. length||4 mi (6.4 km)|
|Max. width||1 mi (1.6 km)|
|Surface area||1,721 acres (7.0 km2)|
|Average depth||9 ft (2.7 m)|
|Max. depth||12 ft (3.7 m)|
|Surface elevation||54 ft (16 m)|
Long Pond is a 1,721-acre (7.0 km2) lake within the towns of Lakeville and Freetown, in southeastern Massachusetts. It shares its waters with Assawompset Pond. These lakes provide a source of drinking water to the city of New Bedford, the largest city in southeastern Massachusetts. Long Pond is roughly one mile (1.6 km) wide by four miles (6.4 km) miles long, and contains three islands within its boundaries. In 1894 Assawompset Pond was dammed, increasing the water depth of Long Pond (which is connected by a small river) by about five feet (1.5 m). This created Nelson Island and caused Sunken Island to disappear due to erosion. All that remains of Sunken Island are the rocks in a shallow area just to the northwest of Lewis Island. Lewis Island is the largest of the three remaining islands today, containing sixteen privately owned cottages, while the second largest island, Nelson Island, was purchased in 2005 and now is a year-round private residence. The smallest island, Goat Island, was recently purchased from the Boy Scouts by a private citizen. Along the perimeter of the lake are many homes and private access points to the waterfront. Long Pond is well known for fishing and boating.
At the northeast corner of the lake is a canal that meanders through the Parkhurst development and is navigable by boat. There is a small bridge that allows foot and road traffic onto the artificial island. In the northwest corner of the lake is a river that feeds into Assawompset Pond, which winds through the marshland before passing under Route 18 and connecting with Assawompset. It is locally known as the "Snake River," but is also labeled as the Long Pond River on some maps.
There are three islands on Long Pond. They are listed from the southernmost to the northernmost island.