Dexter Drumlin is a 311-foot glacial hill and 38-acre open space in Lancaster, Massachusetts, preserving a clear example of the streamlined landforms left by the last glacier more than 10,000 years ago. Its fields, meadows, wetlands, and a tributary of the Nashua River support grassland birds and reflect the area's broader geological and ecological history. The site has also supported scientific research, including Fitchburg State College studies of firefly mating displays and predation. Once known as Kilbourn Hill, it became part of The Trustees of Reservations through Nathaniel Dexter's bequest and is now used for recreation along a one-mile path.