It's the field near the old hospital.  

Directions from East of Leesburg:
Take Route 7 west into Leesburg (Route 7 becomes Market Street).   Just after passing the old courthouse, turn right onto King Street (Route 15).  Then take the second left turn onto North Street and go two blocks before bearing to the right past the School Board Annex building.  Park in the Annex parking lot and the field will be up on the right side.

Directions from West of Leesburg:
Take Route 7 east toward Leesburg and take the Route 7 Business exit to go into downtown Leesburg.  Bear to the left when the street splits and go about a quater mile before turning left onto Wirt Street (just before the traffic light at King Street).  Two blocks later turn left onto North Street and follow it around to the School Board Annex building on the right.  Park in the Annex parking lot and the field will be up on the right side.