Great Meadows National Wildlife Refuge

Great Meadows National Wildlife Refuge
Great Meadows National Wildlife Refuge comprises more than 3,800 acres, 85 percent of which is freshwater wetlands stretching along twelve miles of the Concord and Sudbury Rivers. “Minute Man National Historical Park and Thoreau’s Walden Pond are located nearby.”   Phone 978-443-4661
Here is the Refuge website.   General map.     Brochure.
There is a wheelchair accessible trail around the lake, according to this Yelp review.
From AllTrails: “Concord Unit trail is a 2.7 mile loop trail located near Concord, Massachusetts that features a river and is good for all skill levels.  The trail ….. is accessible from March until November.”  Trails described in the refuge brochure sound easy, but call first to be sure.