Washington DC is the seat of the US Government and has a population of more than 600,000 though its residents do not get a voice in Congress – there have recently been calls to create a 51st State.
DCA Perimeter Rule: Only routes under 1,250 miles…with 10 exceptions
DCA Airport in Washington DC enforces a “perimeter rule” stating that only flights under 1,250 miles are allowed to depart from the airport.