The WMA covers a 40-acre (16 ha) tract of marshy woodland, with two man-made ponds ('impoundments') for wildlife, located between Chesapeake & Ohio Canal towpath (mileposts 20.08 to 20.90[3]) and the Potomac River. The nearest access point is the Pennyfield Lock parking lot at MP 19.7.
Unlike most WMAs in Maryland, Dierrsen is a wildlife sanctuary - no hunting is allowed, but hiking and photography are encouraged. Because of the impoundments and location on the Potomac migration route, the tract is a well-known habitat for waterfowl, wading birds and songbirds. There are nesting boxes for wood ducks. Also present are white-tailed deer, gray and red fox, beaver, and wild turkeys. The site, donated as a waterfowl sanctuary, is named for Marshall Bidwell Dierssen.[4]
^Hahn, Thomas F. Swiftwater (1993). Towpath Guide to the C&O Canal: Georgetown Tidelock to Cumberland, Revised Combined Edition. Shepherdstown, WV: American Canal and Transportation Center. ISBN0-933788-66-5. p. 50