List of Maryland counties and independent city*
- Allegany County: formed in 1789 from part of Washington County. County seat: Cumberland.
- Anne Arundel County: formed in 1650 from unorganized territory. County seat: Annapolis. Was named Providence County between 1654 and 1658.
- Baltimore City: founded in 1729. Detached* in 1851 from Baltimore County.
- Baltimore County: formed in 1659 from unorganized territory. County seat: Towson.
- Calvert County: formed in 1654 as Patuxent County from unorganized territory. Renamed Calvert County in 1658. County seat: Prince Frederick.
- Caroline County: formed in 1789 from parts of Dorchester County and Queen Anne's County. County seat: Denton.
- Carroll County: formed in 1837 from parts of Baltimore County and Frederick County. County seat: Westminster.
- Cecil County: formed in 1672 from parts of Baltimore County and Kent County. County seat: Elkton.
- Charles County: formed in 1658 from unorganized territory. County seat: La Plata.
- Dorchester County: formed in 1668 from unorganized territory. County seat: Cambridge.
- Frederick County: formed in 1748 from part of Prince George's County. County seat: Frederick.
- Garrett County: formed in 1872 from part of Allegany County. County seat: Oakland.
- Harford County: formed in 1773 from part of Baltimore County. County seat: Bel Air.
- Howard County: formed in 1851 from parts of Anne Arundel County and Baltimore County. County seat: Ellicott City.
- Kent County: formed in 1642 from unorganized territory. County seat: Chestertown.
- Montgomery County: formed in 1776 from part of Frederick County. County seat: Rockville.
- Prince George's County: formed in 1695 from parts of Calvert County and Charles County. County seat: Upper Marlboro.
- Queen Anne's County: formed in 1706 from part of Talbot County. County seat: Centerville.
- St. Mary's County: formed in 1637 from unorganized territory. County seat: Leonardtown. Was named Potomac County between 1654 aqnd 1658.
- Somerset County: formed in 1666 from unorganized territory. County seat: Princess Anne.
- Talbot County: formed in 1662 from part of Kent County. County seat: Easton.
- Washington County: formed in 1776 from part of Frederick County. County seat: Hagerstown.
- Wicomico County: formed in 1867 from parts of Somerset County and Worcester County. County seat: Salisbury.
- Worcester County: formed in 1742 from part of Somerset County. County seat: Snow Hill.
*Though an independent city rather than a county, the City of Baltimore is considered the equal of a county for most purposes.
Defunct counties:
- Charles County : formed in 1650 from part of Saint Mary's County. Abolished in 1654.
- Durham County : formed in 1669 from part of Somerset County and nonorganized territory. Abolished in 1672 and incorporated in Worcester County.
- Worcester County : formed in 1672 from part of Durham County and nonorganized territory. Lost in 1685 when Delaware Colony was established.
See also
Sources
