Allegany Formed: 1789 Parent: Washington	Anne Arundel Formed: 1650 Parent: Original County	Baltimore City Formed: 1729 Parent: Baltimore County	Baltimore Formed: 1659 Parent: Original County	Calvert Formed: 1654 Parent: Original County (formerly Patuxent)	Caroline Formed: 1773 Parent: Dorchester and Queen Anne's
Carroll Formed: 1837 Parent: Baltimore and Frederick	Cecil Formed: 1674 Parent: Baltimore and Kent	Charles Formed: 1658 Parent: Original County	Dorchester Formed: 1668 Parent: Original County	Frederick Formed: 1748 Parent: Prince George's	Garrett Formed: 1872 Parent: Allegany
Harford Formed: 1773 Parent: Baltimore	Howard Formed: 1851 Parent: Anne Arundel and Baltimore	Kent Formed: 1642 Parent: Original County	Montgomery Formed: 1776 Parent: Frederick	Prince George's Formed: 1695 Parent: Charles and Calvert	Queen Anne's Formed: 1706 Parent: Talbot
St. Mary's Formed: 1637 Parent: Original County	Somerset Formed: 1666 Parent: Original County	Talbot Formed: 1662 Parent: Kent	Washington Formed: 1776 Parent: Frederick	Wicomico Formed: 1867 Parent: Somerset and Worcester	Worcester Formed: 1742 Parent: Somerset