Trail riding in and around Frederick County, Md

[TheHiriser]

For those that do road and dirt I was wondering if anyone knew of some good places to ride trails or just plain old dirt roads.  I know of some places but maybe haven't heard of others.

Micheaux State Forest (Washington CO) use to allow dirt bikes to ride the dirt roads, not sure if they still do.  I'm not looking for moto-cross parks.  My knees and ankles can't handle that anymore.