Today’s Maryland counties did not always exist in their present form. The borders that define the 24 jurisdictions were formed over the course of three centuries. St. Mary’s County was the first to be organized, and Garrett County was the last.
Below are Maryland’s counties listed in order of formation. Click on the Conduit Street Fun Fact to discover something new about each place!

- 1637 St. Mary’s County
- 1642 Kent County
- 1650 Anne Arundel County
- 1654 Calvert County
- 1658 Charles County
- 1659/60 Baltimore County
- 1661/62 Talbot County
- 1666 Somerset County
- 1668/69 Dorchester County
- 1674 Cecil County
- 1695 Prince George’s County
- 1706 Queen Anne’s County
- 1742 Worcester County
- 1748 Frederick County
- 1773 Caroline County
- 1773 Harford County
- 1776 Montgomery County
- 1776 Washington County
- 1789 Allegany County
- 1796 Baltimore City
- 1837 Carroll County
- 1851 Howard County
- 1867 Wicomico County
- 1872 Garrett County
Do you have a fun fact to share about your county? If so, please send it to Allison Valliant to be featured in MACo’s weekly Fun Fact on Conduit Street.