High Quality Content by WIKIPEDIA articles! The Washington Metropolitan Area, formally known as the Washington?Arlington?Alexandria, DC?VA?MD?WV MSA, is a U.S. Metropolitan Statistical Area (MSA) defined by the United States Office of Management and Budget (OMB) as of November 2004. It is also part of the larger Baltimore-Washington Metropolitan Area.The Washington Metropolitan Area is the most educated and affluent metropolitan area in the United States. As of the 2008 Census Bureau estimate[update], the population of the Washington Metropolitan Area was estimated to be 5,358,130, making it the ninth-largest metropolitan area in the United States.