
| County | Pop. (2000) | Latest Visit | County Seat | Visited? | |
| Allegany | 74,930 | 31-Jul-2005 | Cumberland | yes | |
| Anne Arundel | 489,656 | 21-Sep-2008 | Annapolis | yes | |
| Baltimore | 754,292 | 23-Apr-2009 | Towson | yes | |
| Calvert | 74,563 | 26-Jul-1996 | Prince Frederick | yes | |
| Caroline | 29,772 | 5-Jul-2008 | Denton | yes | |
| Carroll | 150,897 | 30-Jul-2006 | Westminster | ||
| Cecil | 85,951 | 23-Apr-2009 | Elkton | yes | |
| Charles | 120,546 | 22-Jun-2008 | La Plata | yes | |
| Dorchester | 30,674 | 26-Jul-1996 | Cambridge | yes | |
| Frederick | 195,277 | 26-Aug-2007 | Frederick | yes | |
| Garrett | 29,846 | 31-Jul-2005 | Oakland | ||
| Harford | 218,590 | 23-Apr-2009 | Bel Air | yes | |
| Howard | 247,842 | 20-Sep-2008 | Ellicott City | ||
| Kent | 19,197 | 21-Sep-2008 | Chestertown | yes | |
| Montgomery | 873,341 | 29-Jul-2006 | Rockville | yes | |
| Prince George’s | 801,515 | 21-Sep-2008 | Upper Marlboro | ||
| Queen Anne’s | 40,563 | 21-Sep-2008 | Centreville | yes | |
| St. Mary’s | 86,211 | 26-Jul-1996 | Leonardtown | yes | |
| Somerset | 24,747 | 10-Mar-2001 | Princess Anne | yes | |
| Talbot | 33,812 | 5-Jul-2008 | Easton | yes | |
| Washington | 131,923 | 26-Aug-2007 | Hagerstown | yes | |
| Wicomico | 84,644 | 10-Mar-2001 | Salisbury | yes | |
| Worcester | 46,543 | 10-Mar-2001 | Snow Hill | yes | |
| Independent City (included in totals) | |||||
| Baltimore | 651,154 | 23-Apr-2009 | |||