Baltimore is the most populous city in the U.S. state of Maryland, fourth most populous city in the Mid-Atlantic, and the 30th most populous city in the United States with a population of 585,708 in 2020. Baltimore was designated an independent city by the Constitution of Maryland in 1851, and today is the most populous independent city in the United States. As of 2021, the population of the Baltimore metropolitan area was estimated to be 2,838,327, making it the 20th largest metropolitan area in the country. Baltimore is located about 40 miles (64 km) north northeast of Washington, D.C., making it a principal city in the Washington–Baltimore combined statistical area (CSA), the third-largest CSA in the nation, with a 2021 estimated population of 9,946,526. The flag of the city of Baltimore features the “Battle Monument”, which is also the central motif on the city’s seal. 4K Resolution.