De Peyster is a town in St. Lawrence County, New York, USA. The population was 998 at the 2010 census. The name is that of one of the land owners of the region, Frederic de Peyster, grandfather of John Watts de Peyster.
The town was first settled around 1802.
The town was established in 1825 from parts of the Towns of De Kalb and Oswegatchie. The town name was proposed to be "Stilwell" after a prominent resident, but the town was given its current name in the hope of obtaining some benefit from De Peyster.
Residents of note
Patty Ritchie, New York State Senator - raised in De Peyster.