WWII Prisoners in America
Starting in 1942, the United States began moving WWII enemy prisoners to the United States to free up soldiers overseas from guarding them and to ease the need for shipping more rations overseas. Camps were mostly in the South to reduce the costs for heating and prisoners were initially put to work in an industrial capacity. Meanwhile, Fairfax County was an important dairy producing and farming county. War needs stripped much of the farming labor and contracting convict labor was no longer filling the need. During the harvest season of fall 1944, the County Extension agent was able to fulfill only 17 of the more then 200 requests for convicts. The County Board of Supervisors petitioned the federal government for a POW camp with approximately 200 POWs and it was built by June of 1945.
Here is a picture of a similar camp in the South- NOT the one on Lee Highway. 
Safety Concerns
The site was the former State Road Convict camp. The nearest neighbors voiced strong concerns for their safety including several in the Lee-Hi Village subdivision across Lee Highway (Still there! Drive down Village Avenue and check out a pre-Levittown subdivision!). The officials explained that the prisoners coming would speak no English (harder for escapees to assimilate into the locale) and were low level buck privates. He explained the camp would be 400 ft x 200 ft with multiple fences and barbed wire. They said escapees were likely to escape from farms (further away from the camp) and not from the camp itself so the neighborhood was safe. Finally, they explained that the prisoners were being treated and fed very well and escapees were unlikely to even want to leave. The camp was approved.
Operations
While the local men were fighting, working in factories or otherwise unable to sustain their home farms at home, the labor from these German soldiers helped fill in. The farmers picked up the prisoners in the morning and returned them at night.
In Margaret Peck's book Voices of Chantilly, a book about life in the surrounding area throughout this time period, a few local residents remembered working with the Germans.
Lewis Hutchison write: "In the 40's there was a Prisoner of War camp at 29/211 and German POWs would come to the farms to help. Two of the POWs named Fritz and Hans [cphug184: But of course!] helped us during the summer and I was quite fond of them. Fritz drew a picture of me from my school picture, and Hans made me a ring from a quarter and a dime, both of which I still have." He continued by saying they painted another local farmer's roof and as kids they were wondered if they were sending signals to the Germans.
Margie Ann Dick, another local resident said that in the summer of 1945, locals were notified they could us the Germans as labor. After several weeks of getting two new prisoners each day, they petitioned to keep the same two so they would not have to re-explain the process of farming, etc. each day. That was allowed. They could not pronounce the names of the two POWs and called them Bill and Sam. They stayed with the family until November of 1945 and when they left she said it was just like family leaving. The local women were not allowed to talk to the POWs but they did. And were not allowed to feed them, but they did. The POWs were picked up at 7:00 am and returned at 6:00 every day but Sunday. If they were working late, the farmers needed to call the camp and notify the guards. Local farmers would pay the army 35 cents per hour some of which made it to the hands of the prisoners where they could by sodas and cigarettes at the camp canteen.
Closure
By mid-November 1945, the prisoners were gone. One legacy left behind was an unplanned for respect between the farmers and prisoners due to the similarities of their cultures: similar religions, agricultural backgrounds and a sense of order and industriousness.
The camp's cinder block buildings remained until the mid-70's before they were torn down. Before the Wegmans was built, dirt bike trails and a few old cinder blocks covered the woods.
Acknowledgement
I would like to give due credit to Adam D. Herman and Christopher F. Jones for their research and article in Vol. 23 of the Fairfax Historical Society's Annual Publication.
The Hide
The wall hinders good reception. Check it out in Google maps before you leave home- it looks pretty accurate. A good approach is from the north, with the wall to your right.