Constitution Marsh Audubon Center and Sanctuary is a unique and beautiful tidal marsh located in Putnam County, New York, and serves as vital natural habitat for the Hudson River Estuary.  Turn right from the parking lot, walk down the gravel driveway, and begin the Blue Trail over the rocky hill out to the boardwalk to view the marsh. The trail is open dawn to dusk every day. The Visitor Center is open on weekends between Memorial Day and Labor Day from 9am to 4pm. No fee required. No dogs allowed.