Potomac is a census-designated place (CDP) in Montgomery County, Maryland, United States, named for the nearby Potomac River. In 2009 CNNMoney.com listed Potomac as the seventh most affluent town in all the United States. Potomac is also the seventh most top-educated American small town according to Forbes. In addition, Bloomberg Businessweek labeled Potomac as the twenty-ninth richest zip code in all of the United States in 2011 and had the largest population of any U.S. town to have a median income of more than $240,000. It is also tied with three other zip codes (all within the Upper West Side or Upper East Side of Manhattan) for the greatest concentration of the "1 percent" in America. Many Potomac residents work in nearby Washington, D.C.