Baltimore is the most populous city in the U.S. state of Maryland, as well as the 30th most populous city in the United States, with an estimated population of 593,490 in 2019. Baltimore was designated an independent city by the Constitution of Maryland in 1851, and today is the largest independent city in the United States. As of 2017, the population of the Baltimore metropolitan area was estimated to be just under 2.802 million, making it the 21st largest metropolitan area in the country. Baltimore is located about 40 miles (64 km) northeast of Washington, D.C., making it a principal city in the Washington–Baltimore combined statistical area (CSA), the fourth-largest CSA in the nation, with a calculated 2018 population of 9,797,063.
