Bay Circuit Trail is a hiking trail in Wayland, Massachusetts. It is within Cow Common and Great Meadows National Wildlife Refuge. It is 2.4 miles long and begins at 126 feet altitude. Traveling the entire trail is 2.9 miles with a total elevation gain of 159 feet. Near the trailhead there are parkings. The Great Meadows National Wildlife Refuge conservation can be seen along the trail. There is also a viewpoint along the trail.