Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| 18 Reservoir | Reservoir | 36 | Anne Arundel | 39 04 54 N | 076 43 59 W |
| 270 Corporate Center | Locale | 158 | Montgomery | 39 11 27 N | 077 15 48 W |
| 270 Industrial Park | Locale | 135 | Montgomery | 39 06 18 N | 077 10 44 W |
| A B Demarco Memorial Park | Park | 65 | Harford | 39 31 25 N | 076 10 37 W |
| A Hill Camping Area | Locale | 1 | Somerset | 38 06 24 N | 075 51 01 W |
| A Hill Cemetery | Cemetery | 0 | Somerset | 38 06 29 N | 075 50 56 W |
| A M Powell State Fish Hatchery | Locale | 166 | Washington | 39 35 32 N | 077 38 15 W |
| A W Wilson Memorial United Methodist Church | Church | 75 | Baltimore (city) | 39 19 54 N | 076 37 03 W |
| Aaron Cove | Cape | -11 | Dorchester | 38 21 58 N | 076 15 06 W |
| Aaron Run | Stream | | Garrett | 39 29 11 N | 079 04 57 W |
| Abbey Creek | Stream | | Harford | 39 21 09 N | 076 14 01 W |
| Abbey Point | Cape | 3 | Harford | 39 20 58 N | 076 13 40 W |
| Abbott Cove | Bay | 3 | Queen Anne's | 39 01 05 N | 076 09 54 W |
| Abbott Memorial Presbyterian Church | Church | 31 | Baltimore (city) | 39 17 16 N | 076 34 07 W |
| Abbottston Elementary School | School | 62 | Baltimore (city) | 39 19 29 N | 076 35 59 W |
| Abe Mills Mountain | Summit | 409 | Washington | 39 40 12 N | 077 58 12 W |
| Abell | Populated Place | 3 | St. Mary's | 38 15 15 N | 076 44 37 W |
| Abell Post Office | Post Office | 3 | St. Mary's | 38 15 17 N | 076 44 38 W |
| Abell School | School | 6 | St. Mary's | 38 15 37 N | 076 45 32 W |
| Abells Wharf | Locale | 3 | St. Mary's | 38 15 40 N | 076 38 47 W |
| Aberdeen | Populated Place | 29 | Harford | 39 30 34 N | 076 09 51 W |
| Aberdeen Branch Harford County Library | Building | 28 | Harford | 39 30 45 N | 076 09 50 W |
| Aberdeen Creek | Bay | -5 | Anne Arundel | 38 56 41 N | 076 31 17 W |
| Aberdeen Festival Park | Park | 29 | Harford | 39 30 41 N | 076 09 49 W |
| Aberdeen Fire Department Company 2 House 1 | Building | | Harford | 39 51 22 N | 076 16 53 W |
| Aberdeen Fire Department Company 2 House 2 | Building | | Harford | 39 51 03 N | 076 16 13 W |
| Aberdeen Fire Department Company 2 House 3 | Building | | Harford | 39 52 21 N | 076 17 24 W |
| Aberdeen High School | School | 49 | Harford | 39 30 58 N | 076 10 17 W |
| Aberdeen Hills (subdivision) | Populated Place | 61 | Harford | 39 31 33 N | 076 10 37 W |
| Aberdeen Industrial Center | Locale | 18 | Harford | 39 29 22 N | 076 10 48 W |
| Aberdeen Market Place Shopping Center | Locale | 60 | Harford | 39 31 18 N | 076 10 54 W |
| Aberdeen Middle School | School | 39 | Harford | 39 30 54 N | 076 09 53 W |
| Aberdeen Park | Park | 112 | Montgomery | 39 05 58 N | 077 15 31 W |
| Aberdeen Police Department | Building | | Harford | 39 51 16 N | 076 16 45 W |
| Aberdeen Post Office | Post Office | 31 | Harford | 39 30 34 N | 076 09 55 W |
| Aberdeen Proving Ground Post Office | Post Office | 13 | Harford | 39 28 56 N | 076 07 49 W |
| Aberdeen Swim Club | Locale | 49 | Harford | 39 32 10 N | 076 09 57 W |
| Abiding Presence Lutheran Church | Church | 72 | Prince George's | 39 02 34 N | 076 55 29 W |
| Abiding Savior Lutheran Church | Church | 125 | Howard | 39 11 52 N | 076 53 00 W |
| Abingdon | Populated Place | 51 | Harford | 39 27 44 N | 076 16 45 W |
| Abingdon Elementary School | School | 62 | Harford | 39 28 40 N | 076 19 31 W |
| Abingdon Fire Company | Building | | Harford | 39 47 30 N | 076 29 29 W |
| Abingdon Landfill | Locale | 25 | Harford | 39 27 10 N | 076 16 58 W |
| Abingdon Post Office | Post Office | 71 | Harford | 39 28 40 N | 076 18 35 W |
| Abingdon Reserve | Populated Place | 55 | Harford | 39 27 57 N | 076 16 59 W |
| Abington Cove | Bay | -3 | Calvert | 38 36 11 N | 076 40 11 W |
| Abington Farm | Locale | 37 | Anne Arundel | 39 02 38 N | 076 37 60 W |
| Abington Shores | Populated Place | 7 | Calvert | 38 35 07 N | 076 40 04 W |
| Abraham Church | Church | 227 | Baltimore | 39 38 39 N | 076 47 21 W |
| Academy Acres | Populated Place | 191 | Baltimore | 39 26 53 N | 076 48 07 W |
| Academy Acres | Populated Place | 243 | Carroll | 39 27 34 N | 077 02 03 W |
| Academy Grove Historic District | Park | 1 | Somerset | 38 06 26 N | 075 47 17 W |
| Academy Heights | Populated Place | 135 | Baltimore | 39 16 55 N | 076 43 22 W |
| Academy Hill | Populated Place | 42 | Calvert | 38 39 35 N | 076 39 42 W |
| Academy Hills | Populated Place | 67 | Cecil | 39 39 24 N | 075 51 19 W |
| Academy Junction | Populated Place | 40 | Anne Arundel | 39 05 22 N | 076 41 54 W |
| Academy Junction Plaza Shopping Center | Locale | 42 | Anne Arundel | 39 05 09 N | 076 41 49 W |
| Academy Lane | Populated Place | 181 | Baltimore | 39 26 08 N | 076 47 11 W |
| Academy Public School (historical) | School | 3 | Dorchester | 38 34 30 N | 076 04 38 W |
| Accident | Populated Place | 727 | Garrett | 39 37 43 N | 079 19 11 W |
| Accident Elementary School | School | 724 | Garrett | 39 37 38 N | 079 19 15 W |
| Accident Evangelical Lutheran Church | Church | 733 | Garrett | 39 37 51 N | 079 19 05 W |
| Accident Volunteer Fire Department | Building | 724 | Garrett | 39 37 40 N | 079 19 09 W |
| Acco Park | Populated Place | 62 | Prince George's | 38 40 26 N | 076 59 60 W |
| Accokeek | Populated Place | 58 | Prince George's | 38 40 03 N | 077 01 42 W |
| Accokeek Acres | Populated Place | 62 | Prince George's | 38 40 07 N | 076 59 36 W |
| Accokeek Branch Library | Building | 59 | Prince George's | 38 40 09 N | 077 01 43 W |
| Accokeek Branch Prince George's County Memorial Library | Building | 58 | Prince George's | 38 40 11 N | 077 01 34 W |
| Accokeek Lawn | Populated Place | 54 | Prince George's | 38 40 10 N | 077 02 19 W |
| Accokeek Neighborhood Park | Park | 58 | Prince George's | 38 40 08 N | 077 01 32 W |
| Accokeek Post Office | Post Office | 58 | Prince George's | 38 39 54 N | 077 01 60 W |
| Accokeek School (historical) | School | 56 | Prince George's | 38 40 07 N | 077 01 36 W |
| Accokeek Volunteer Fire Department Company 24 | Building | | Prince George's | 39 07 04 N | 077 03 06 W |
| Ackerson Hall | Building | 93 | Baltimore (city) | 39 22 11 N | 076 39 19 W |
| Acorn Hill Childrens Center | School | 82 | Montgomery | 39 00 41 N | 077 01 22 W |
| Acquango Branch | Stream | | Worcester | 38 13 02 N | 075 22 07 W |
| Acre Creek | Bay | -3 | Somerset | 38 01 40 N | 075 50 52 W |
| Acre Marsh | Swamp | 0 | Somerset | 38 00 39 N | 075 51 26 W |
| Acredale | Populated Place | 32 | Prince George's | 39 00 10 N | 076 56 34 W |
| Acresville | Populated Place | 12 | Anne Arundel | 39 10 40 N | 076 36 41 W |
| Acton Cove | Bay | 0 | Anne Arundel | 38 58 27 N | 076 29 32 W |
| Acton Square Shopping Center | Locale | 62 | Charles | 38 38 08 N | 076 53 59 W |
| Acton Village | Populated Place | 62 | Charles | 38 38 26 N | 076 54 19 W |
| Adam Island | Island | 0 | Dorchester | 38 08 41 N | 076 05 15 W |
| Adams Chance | Populated Place | 232 | Carroll | 39 34 33 N | 076 52 54 W |
| Adams Church | Church | 21 | Anne Arundel | 38 50 42 N | 076 40 39 W |
| Adams Creek | Stream | | St. Mary's | 38 09 35 N | 076 28 43 W |
| Adams Heights | Populated Place | 89 | Harford | 39 32 16 N | 076 10 49 W |
| Adams Landing | Locale | 6 | Caroline | 38 54 04 N | 075 49 47 W |
| Adams Mobile Home Park | Populated Place | 18 | Harford | 39 31 47 N | 076 07 34 W |
| Adams Point | Cape | 0 | Anne Arundel | 39 03 18 N | 076 27 10 W |
| Adamstown | Populated Place | 93 | Frederick | 39 18 39 N | 077 28 29 W |
| Adamstown Post Office | Post Office | 92 | Frederick | 39 18 40 N | 077 28 31 W |
| Adamstown Public School (historical) | School | 94 | Frederick | 39 18 29 N | 077 28 32 W |
| Adamstown Village | Populated Place | 104 | Frederick | 39 19 00 N | 077 30 23 W |
| Adath Israel Cemetery | Cemetery | 5 | Baltimore | 39 16 54 N | 076 29 43 W |
| Adath Yeshuron Synagogue | Church | 129 | Baltimore (city) | 39 20 39 N | 076 40 04 W |
| Addison Chapel | Church | 45 | Prince George's | 38 53 56 N | 076 54 35 W |
| Addison Chapel Cemetery | Cemetery | 44 | Prince George's | 38 53 57 N | 076 54 36 W |
| Addison Point | Cape | 12 | Anne Arundel | 38 57 31 N | 076 34 23 W |
| Addison Road-Seat Pleasant Metro Station | Locale | 49 | Prince George's | 38 53 11 N | 076 53 50 W |
| Addison Run | Stream | | Frederick | 39 26 38 N | 077 21 51 W |
| Addison School | School | 53 | Prince George's | 38 47 30 N | 077 00 11 W |
| Adelina | Populated Place | 37 | Calvert | 38 28 50 N | 076 37 17 W |
| Adelphi | Populated Place | 52 | Prince George's | 39 00 11 N | 076 58 19 W |
| Adelphi Bible Church | Church | 42 | Prince George's | 38 59 42 N | 076 58 23 W |
| Adelphi Elementary School | School | 53 | Prince George's | 39 00 02 N | 076 58 27 W |
| Adelphi Mill Recreation Center | Park | 30 | Prince George's | 38 59 34 N | 076 58 19 W |
| Adelphi Park | Populated Place | 22 | Prince George's | 38 59 11 N | 076 58 05 W |
| Adelphi Plaza Shopping Center | Locale | 22 | Prince George's | 38 59 05 N | 076 58 03 W |