Harford/B'more CO, MD
-
It may be a little far for you but there is a GREAT dog part at Quiet Waters Park in Annapolis, it also has a dog beach. I used to go there all the time when I lived in the area.
Here's a link that has a huge list of dog parks and on/off leash areas in Maryland
http://www.ecoanimal.com/dogfun/maryland.html