The Walney Visitor Center is part of the Ellanor C.Lawrence Park. This park component is a partially restored farm that was active from the 1700s into the 1900s.
It looks like Fairfax County Park Authority has let basic maintenance slide at this facility. It is rather dirty and ill kept too.
Some historical information about the Walney Farm is displayed in the lower level of the farm house, which serves as the Ellanor C. Lawrence Park visitor center. I found inconsistencies in the information and asked about them. A knowledgeable park employee clarified the information for me--I was correct about inconsistency--but he did not at all appear concerned with taking action to see that the problem was corrected for future visitors. I suppose having clear and correct information is not in the budget.
The highlights of the Walney Farm exhibit are the living animal displays of snakes, lizards, turtles, frogs and toads. Those are the only parts of the visitor center which are obviously kept maintained, fortunately for the confined creatures.
One farm outbuilding survives (a smokehouse). Additionally, the footings and foundations of other buildings can be viewed, along with the garden vegetable plots for the farmhouse. The historical signage on the grounds is so weathered it is unreadable in places. Some historical displays are rotting and collapsing.
Nature trails are in the woods behind Walney Farm, though I did not follow any.
About a 1/2 mile away is historic Cabell's Mill, which serves as park offices and has a restored historic building available for functions by reservation. That component of the park is much better maintained than Walney Farm, although it is not open to the general public except to gawk at from outside.
Ellanor C. Lawrence Park is very large. A couple miles from Walney Farm are athletic fields that are very nice. It's a pity the historic portion of the park open to the public gets so little attention from Fairfax County compared to the athletic fields. Perhaps in 200 years the goals, portable toilets and trash cans at the athletic fields will be treated as rare and revered relics from the past.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.