Great Meadows National Wildlife Refuge has two branches. The Concord Unit is 1.3 mi. e. on SR 62, then n. on Monsen Rd. The Sudbury Unit is on Weir Hill Rd. in Sudbury. The refuge includes nature and interpretive trails along the river, wetland and forested upland. Bird-watching at the Concord Unit is excellent during the spring and fall.
Note: Dogs and bicycles are not permitted at the refuge.