http://maps.google.com/maps?f=d&hl=en&q=1659%20Old%20Chain%20Bridge%20Road+McLean,+VA+

From the Capital Beltway in Virginia: 
Take the Route 123 exit toward McLean
Go about a half-mile and turn right at the 4th traffic light on to Great Falls Street
Go one long block and turn left at the first traffic light on to Chain Bridge Road
Follow Chain Bridge about a half-mile and turn right into the park
Fields #2 is the lighted field to the left behind the trees as you enter the parking lot