Admitted to the Union on April 28, 1788 as the 7th state.

• 1790 federal census extant for all counties except Allegany, Calvert, and Somerset are lost. Much of Dorchester is also lost.
• 1800 federal census extant for all counties except Baltimore County outside the city of Baltimore is lost.
• 1810 – 1820 federal censuses extant for all counties.
• 1830 federal census extant for all counties except Montgomery, Prince George’s, Queen Anne’s, St. Mary’s, and Somerset.
• 1840 – 1940 federal censuses extant for all counties except for 1890.