MARYLAND: Click this link to see all slave labor sites in the state.
- Statehood: 1776
- COUNTIES: Click one of the counties below to see all plantations/ workplaces in that county.
| County | Year Est. | Details |
| Allegany | 1789 | from Washington Co. |
| Anne Arundel | 1650 | |
| Baltimore | 1659 | |
| Baltimore City | 1729 | from Baltimore Co. |
| Calvert | 1654 | Patuxent Co. renamed Calvert Co. in 1654 |
| Caroline | 1773 | from Dorchester and Queen Anne’s Counties |
| Carroll | 1837 | from Baltimore and Frederick Counties |
| Cecil | 1674 | from Baltimore and Kent Counties |
| Charles | 1658 | |
| Dorchester | 1668 | |
| Frederick | 1748 | from Prince George’s Co. |
| Garrett | 1872 | from Allegany Co. (last county to be formed in Maryland) |
| Harford | 1773 | from Baltimore Co. |
| Howard | 1851 | from Anne Arundel and Baltimore Counties |
| Kent | 1642 | |
| Montgomery | 1776 | from Frederick Co. |
| Prince George’s | 1695 | from Charles and Calvert Counties |
| Queen Anne’s | 1706 | from Talbot Co. |
| St. Mary’s | 1637 | |
| Somerset | 1666 | |
| Talbot | 1662 | from Kent Co. |
| Washington | 1776 | from Frederick Co. |
| Wicomico | 1867 | from Somerset and Worcester Counties |
| Worcester | 1742 | from Somerset Co. |