John S. Long Park - Haymarket

Directions unearthed via the web:

John S. Long Park - Haymarket
ADC Map: Prince William (2001 Edition) Map 3-K4
4603 James Madison Highway
Haymarket, Virginia 20169

From Centreville - Take I-66 West and proceed to Exit 40.
Take Exit 40 for Route 15 (Haymarket) and turn right off the exit ramp (toward Leesburg).
Follow Route 15 North about 2 miles to the park entrance.
Turn right into John Long Park.
Take the first left after entering the park.
The Under 14, 16, and 19 teams should pass the first parking area and park at the top of the hill by the playground.
The field is the large field below the hill.
Long park is about a 15 minute drive from Centreville (at least, it should be on a Saturday).

Directions gleaned from:
Prince William County website - for the library, but the same location.

Here’s a map, from Prince William County (it's really, really big - may take a minute to open):