National Harbor DC WaterfrontA luxury resort, retail, dining, entertainment and gaming experience just minutes from Washington D.C on the banks of the Potomac River.Casino · Casino Promotions · Restaurants · Entertainment. Browse Casinos in Washington & save money with our Expedia Price Guarantee. Read user reviews of over hotels worldwide. No Expedia. Information on MGM National Harbor Casino in Washington D.C., including description and review, hours, address, phone number and map of MGM National.