Lake Singletary is located in Massachusetts bordering the towns of Millbury and Sutton. The greater part of the 330 acre lake is located in Sutton with the main inlet (Welsh Pond) located at West Sutton Road, while the remaining part of the lake is located in Millbury with its outlet (Singletary Stream) located at Harris Avenue, which flows south-easterly through Millbury before joining the Blackstone River. There are two islands on the lake, “Loon Island” near the western end, and "Fire Island” nears the eastern shore. The lake sits 559 feet above sea level with a maximum depth of 39 feet. The 6.0 mile long shoreline supports 163 homes with a public boat ramp in Millbury and a town beach (Marion’s Camp) in Sutton.
Lake Singletary played an important role throughout American history. During the Industrial Revolution, Lake Singletary (then called Crooked Pond) supplied power to the mills built along the Singletary Stream outlet, formerly called Mill Brook. In 1720 John Singletary purchased land along the Singletary Stream from Ebenezer Daggett. Shortly after John established the first gristmill in Millbury and later added a sawmill. John and his son Amos kept these mills in operation for many years. In fact the gristmill (known today as S & D Spinning Mill), is still in operation, making it one of the oldest continuously operating mills in the United States. Rumor has it that the original water turbine is still in the basement of the mill. Throughout the 1700’s and 1800’s several more mills were erected along the Singletary Stream, manufacturing goods such as flour, cotton, paper, guns, scythes, horseshoes, and many other farm equipment items. Lake Singletary was also a major source of ice for the Worcester County area when Warren A. Harris built and operated his 2,500 ton Ice House.