Baltimore is the largest city in the U.S. state of Maryland, and the 29th-most populous city in the country. It was established by the Constitution of Maryland and is not part of any county, thus it is the largest independent city in the United States. Baltimore has more public monuments than any other city per capita in the country and is home to some of the earliest National Register historic districts in the nation, including Fell's Point (1969), Federal Hill (1970) and Mount Vernon Place (1971). More than 65,000 properties, or roughly one in three buildings in the city, are listed on the National Register, more than any other city in the nation.

Founded in 1729, Baltimore is the second largest seaport in the Mid-Atlantic. Baltimore's Inner Harbor was once the second leading port of entry for immigrants to the United States and a major manufacturing center. After a decline in major manufacturing, industrialization and rail transportation, Baltimore shifted to a service-oriented economy, with the Johns Hopkins Hospital (founded 1889), and Johns Hopkins University (founded 1876), now the city's top two employers.
Baltimore had a population of 621,849 in 2015; in 2010, that of Baltimore Metropolitan Area was 2.7 million, the 21st largest in the country.

With hundreds of identified districts, Baltimore has been dubbed "a city of neighborhoods". Famous residents have included the writers Edgar Allan Poe, Edith Hamilton, Frederick Douglass, and H.L. Mencken; jazz musician James "Eubie" Blake; singer Billie Holiday; actor and filmmaker John Waters; and baseball player Babe Ruth. In the War of 1812, Francis Scott Key wrote The Star-Spangled Banner, later the American national anthem, in the city.

Almost a quarter of the jobs in the Baltimore region are in science, technology, engineering and math, in part attributed to its extensive undergraduate and graduate schools.