
| County | Pop. (2010) | Latest Visit | County Seat | Visited? | |
| Allegany | 75,087 | 31-Jul-2005 | Cumberland | yes | |
| Anne Arundel | 537,656 | 19-Aug-2012 | Annapolis | yes | |
| Baltimore | 805,029 | 8-Aug-2012 | Towson | yes | |
| Calvert | 88,737 | 26-Jul-1996 | Prince Frederick | yes | |
| Caroline | 33,066 | 5-Jul-2008 | Denton | yes | |
| Carroll | 167,134 | 25-Nov-2011 | Westminster | ||
| Cecil | 101,108 | 19-Aug-2012 | Elkton | yes | |
| Charles | 146,551 | 22-Jun-2008 | La Plata | yes | |
| Dorchester | 32,618 | 26-Jul-1996 | Cambridge | yes | |
| Frederick | 233,385 | 3-Sep-2012 | Frederick | yes | |
| Garrett | 30,097 | 31-Jul-2005 | Oakland | ||
| Harford | 244,826 | 8-Aug-2012 | Bel Air | yes | |
| Howard | 287,085 | 8-Aug-2012 | Ellicott City | yes | |
| Kent | 20,197 | 19-Aug-2012 | Chestertown | yes | |
| Montgomery | 971,777 | 3-Sep-2012 | Rockville | yes | |
| Prince George’s | 863,420 | 19-Aug-2012 | Upper Marlboro | ||
| Queen Anne’s | 47,798 | 19-Aug-2012 | Centreville | yes | |
| St. Mary’s | 105,151 | 26-Jul-1996 | Leonardtown | yes | |
| Somerset | 26,470 | 10-Mar-2001 | Princess Anne | yes | |
| Talbot | 37,782 | 5-Jul-2008 | Easton | yes | |
| Washington | 147,430 | 2-Sep-2012 | Hagerstown | yes | |
| Wicomico | 98,733 | 4-Jul-2010 | Salisbury | yes | |
| Worcester | 51,454 | 10-Mar-2001 | Snow Hill | yes | |
| Independent City (included in totals) | |||||
| Baltimore | 620,961 | 8-Aug-2012 | |||