Fly with Austrian Airlines to Washington and experience the center of federal government of the USA. Washington DC is a federal district and is the capital city of the USA, situated on the north bank of the river Potomac, and bordered to the southwest by the state of Virginia and the remainder by the state of Maryland. Washington covers an area of 177 sq km, of which just over 10% is water, and a little more than 19% is parkland. The city was designed as a low rise area, and as a consequence of this, there is a certain urban sprawl resulting in traffic congestion. The resident population was estimated at about 600,000 in 2009, although weekday population is swollen by commuting workers to over 1 million.