Maryland
- Charles County: formed in 1650 from part of Saint Mary's County. Abolished in 1654. Referred to as Old Charles County.
- 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.
Read more about this topic: List Of Former United States Counties