http://www.howlbrew.org/ Homebrewers Of Western Loudoun. We meet at Corcoran Winery & Brewing Company outside of Waterford, just a bit west of Leesburg. There's a Facebook group too.
Do you keg, by chance? If so, where do you fill your CO2 bottles? I was thinking of taking my tank over to Check It Paintball, buf figured I'd see what other locals have done in the area...