The Province of Maryland was a proprietary colony, in the hands of the Calvert family, who held it from 1633 to 1689, and again from 1715 to 1776. George Calvert, 1st Baron Baltimore (1580–1632) is often regarded as the founder of Maryland, but he died before the colony could be organized.
| No. | Proprietor | Term | |
|---|---|---|---|
| 1 | Cecil Calvert, 2nd Baron Baltimore (1605–1675) | 15 April 1632 – 30 November 1675 | |
| 2 | Charles Calvert, 3rd Baron Baltimore (1637–1715) | 30 November 1675 – 1689 | |
| Vacant | |||
| 3 | Charles Calvert, 5th Baron Baltimore (1699–1751) | 16 April 1715 – 24 April 1751 | |
| 4 | Frederick Calvert, 6th Baron Baltimore (1731–1771) | 24 April 1751 – 4 September 1771 | |
| 5 | Henry Harford (1758–1834) | 4 September 1771 – 4 July 1776 | |