[egor20]

For Maryland.
CARRYING AND TRANSPORTATION IN VEHICLES

Rifles and shotguns being transported in motor vehicles must be unloaded.

It is a crime to wear or carry openly any rifle or shotgun with the intent or purpose of unlawfully injuring any person.

For Washington D.C.
In Washington, D.C., all firearms must be registered with the police, by the terms of the Firearms Control Regulations Act of 1975.

I live in NOVA and don't carry any weapons (even a folding knife) when I go to MD or D.C.