There is a Muso Jikiden Eishin Ryu dojo in Woodbridge http://www.eishinkai.homestead.com/
There is also a Nakamura Ryu dojo in the area run by Dave Drawdy in Arlington, Va http://www.geocities.com/nvbudokai/batto-do.htm
Both are very reputable dojos.
I'd also suggest doing searches at both http://www.e-budo.com
for cities and state names in your area. There are other places, but I can't recall any off the top of my head.