Troy Meadows in Parsippany, New Jersey, is a 3,100-acre preserve and the state’s largest freshwater marsh. Together with the Great Swamp, it preserves part of the former bed of Glacial Lake Passaic, through which the Whippany River flows toward the Rockaway River. The marsh reflects ancient geologic shaping and later glacial retreat, after the Wisconsin Glacier covered the area and melting formed, then drained, the lake that left these meadows behind. Designated a National Natural Landmark in 1967, Troy Meadows endures as an important remnant of a much larger lake landscape and a rare major wetland in heavily developed northern New Jersey.