Oxbow National Wildlife Refuge (NWR) is located in north-central Massachusetts, approximately 35 miles northwest of Boston, MA. The refuge lies within the towns of Ayer and Shirley in Middlesex County and the towns of Harvard and Lancaster in Worcester County. The refuge consists of approximately 1,667acres of upland, southern New England flood-plain forest, and wetland communities along nearly 8 miles of the Nashua River corridor.