The official name is the District of Columbia, an independent territory that does not belong to any of the states. The city was founded in 1791 and is named after George Washington, the first American president. Since 1871, Washington, along with Georgetown and a number of other territories, is united in the District of Columbia (English, District of Columbia, abbreviated to D.C.). The boundaries of the district coincide with the city, so the Americans, in order not to confuse the city with the same state in the north-west of the country, usually call the city "Washington DC".

As of 2016, the population is estimated at 681,170, which is raised to more than one million during the work week by commuters from the nearby Maryland and Virginia suburbs.

The supreme authority over the city is held by congress. But the city has had a locally elected mayor and a council of 13 since 1973.

More Info: en.wikipedia.org