Washington D.C. is in the United States.
United States . The capital is Washington , D.C. , and the largest city is New York City ; nine other major metropolitan areas -- each with at least 4.5 million inhabitants and the largest having more than 13 million people -- are Los Angeles , Chicago , Dallas , Houston , Philadelphia , Miami , Atlanta , Boston , and San Francisco . Washington ( [ ˈwɒʃɪŋtən ] ) is a state in the Pacific Northwest region of the United States located north of Oregon , west of Idaho , and south of the Canadian province of British Columbia on the coast of the Pacific Ocean .