The 360-acre Tennant Lake unit, about one mile southeast of Ferndale, is mostly in the floodplain of the Nooksack River. Some of the lower portions flood annually. Tennant Lake itself is an 80-acre, shallow, peat-bog lake. One half mile south of this lake is Claypit Pond, formed as clay was dug up to manufacture brick and glass (prior to WDFW ownership). Fairly extensive swamp/marsh areas occur adjacent to both lakes. Initially the area was primarily managed for waterfowl and deer hunting, and spiny-ray fishing. There is now also an interpretive center and scent garden for the blind, an observation tower, upland interpretive trail, an elevated wetland boardwalk trail, and a boat launch on the Nooksack River. These improvements, along with WDFW staff at the interpretive center, provide important recreational and educational opportunities for school districts and general visitors.