George Washington was responsible for the defeat of the British which led to the creation of the USA. Washington chose the site for the Capital, and as "The Father of his country", it was felt naming...
The capital of the US is named very appropriately after the first President, without whom there would have been no US. Washington was a great President whose leadership was essential to the success...
Washington State is indeed the only state named after a former US President, having been named after first President of the United States George Washington.