Washington, D.C. criminal defense lawyer Nabeel Kibria explains when a person can use a firearm in self-defense in Washington, D.C. He notes that a person may use a gun or firearm only in self-defense. In Washington, D.C., the lawful use of a firearm is limited to defending oneself in the home or place of business. Beyond that, there is no valid defense for using a firearm, as firearms can never be used offensively under the law in either Washington, D.C. or the United States.