Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Anthony | Populated Place | 10 | Caroline | 38 52 40 N | 075 47 18 W |
| Anthony Ridge | Ridge | 353 | Allegany | 39 33 52 N | 078 28 20 W |
| Anthonyville | Populated Place | 61 | Baltimore (city) | 39 20 16 N | 076 33 07 W |
| Antietam | Populated Place | 94 | Washington | 39 24 58 N | 077 44 32 W |
| Antietam Church of God | Church | 127 | Washington | 39 25 21 N | 077 44 37 W |
| Antietam Creek | Stream | | Washington | 39 25 02 N | 077 44 44 W |
| Antietam Creek Aqueduct | Bridge | 85 | Washington | 39 25 02 N | 077 44 46 W |
| Antietam Creek Campground | Locale | 88 | Washington | 39 25 05 N | 077 44 44 W |
| Antietam Dargan Community Park | Park | 166 | Washington | 39 22 37 N | 077 43 56 W |
| Antietam Farmettes | Populated Place | 139 | Washington | 39 31 25 N | 077 42 42 W |
| Antietam Heights | Populated Place | 127 | Washington | 39 28 35 N | 077 41 42 W |
| Antietam Iron Works (historical) | Locale | 90 | Washington | 39 25 00 N | 077 44 27 W |
| Antietam Manor | Populated Place | 150 | Washington | 39 31 45 N | 077 44 43 W |
| Antietam National Battlefield | Park | 146 | Washington | 39 28 15 N | 077 44 15 W |
| Antietam National Cemetery | Cemetery | 153 | Washington | 39 27 33 N | 077 44 29 W |
| Antietam Overlook | Populated Place | 156 | Washington | 39 31 17 N | 077 41 54 W |
| Antietam Professional Center | Building | 164 | Washington | 39 38 21 N | 077 43 03 W |
| Antietam School | School | 164 | Washington | 39 38 20 N | 077 43 01 W |
| Antietam Station | Locale | 143 | Washington | 39 27 06 N | 077 46 08 W |
| Antietam Village (subdivision) | Populated Place | 100 | Frederick | 39 26 20 N | 077 24 51 W |
| Antietam Village Shopping Center | Locale | 98 | Frederick | 39 26 20 N | 077 24 41 W |
| Antioch Cemetery | Cemetery | 2 | Dorchester | 38 32 58 N | 076 09 24 W |
| Antioch Cemetery | Cemetery | 4 | Somerset | 38 12 04 N | 075 41 35 W |
| Antioch Chapel | Church | 6 | Baltimore | 39 15 07 N | 076 27 31 W |
| Antioch Church | Church | 30 | Anne Arundel | 39 01 28 N | 076 29 58 W |
| Antioch Church | Church | 2 | Dorchester | 38 32 58 N | 076 09 24 W |
| Antioch Church | Church | 4 | Somerset | 38 12 04 N | 075 41 32 W |
| Antler Creek | Stream | | Cecil | 39 28 58 N | 075 58 24 W |
| Anton North | Populated Place | 142 | Baltimore | 39 24 07 N | 076 43 27 W |
| Anton Woods | Populated Place | 132 | Baltimore | 39 24 00 N | 076 43 33 W |
| Ape Hole Creek | Bay | -3 | Somerset | 37 57 30 N | 075 49 09 W |
| Apostolic Christian Church | Church | 59 | Prince George's | 38 45 37 N | 076 49 53 W |
| Apostolic Church of God | Church | 19 | Queen Anne's | 39 06 05 N | 075 57 07 W |
| Apostolic Faith Church of God Number 1 | Church | 71 | Baltimore (city) | 39 18 38 N | 076 38 59 W |
| Apostolic Faith Church of Jesus | Church | 44 | Calvert | 38 42 14 N | 076 37 13 W |
| Appalachian National Scenic Trail | Trail | 349 | Washington | 39 20 44 N | 077 40 15 W |
| Appeal | Populated Place | 27 | Calvert | 38 22 03 N | 076 26 54 W |
| Appeal School | School | 29 | Calvert | 38 22 32 N | 076 26 13 W |
| Apple Greene | Populated Place | 36 | Calvert | 38 42 58 N | 076 39 14 W |
| Apple Grove | Populated Place | 37 | Prince George's | 38 47 18 N | 076 57 39 W |
| Apple Grove Elementary School | School | 45 | Prince George's | 38 47 19 N | 076 57 46 W |
| Apple Grove Plantation (historical) | Locale | 43 | Prince George's | 38 47 23 N | 076 57 46 W |
| Apple Resource Center | Building | | Frederick | 39 42 15 N | 077 42 37 W |
| Apple Ridge | Populated Place | 76 | Baltimore | 39 22 45 N | 076 30 39 W |
| Applegarth (historical) | Populated Place | 0 | Dorchester | 38 14 41 N | 076 08 24 W |
| Applegate (subdivision) | Populated Place | 103 | Frederick | 39 26 05 N | 077 24 50 W |
| Apples Cemetery | Cemetery | 141 | Frederick | 39 37 52 N | 077 23 45 W |
| Apples Church | Church | 136 | Frederick | 39 37 50 N | 077 23 44 W |
| Appleton | Populated Place | 105 | Cecil | 39 41 54 N | 075 48 51 W |
| Appleton Acres | Populated Place | 104 | Cecil | 39 42 05 N | 075 49 01 W |
| Appleton Glen | Populated Place | 88 | Cecil | 39 42 15 N | 075 48 54 W |
| Appletown | Populated Place | 177 | Washington | 39 28 50 N | 077 38 51 W |
| Appleview Farms | Locale | 131 | Harford | 39 43 05 N | 076 17 37 W |
| Appolds | Populated Place | 134 | Frederick | 39 37 38 N | 077 19 18 W |
| April Estates | Populated Place | 35 | Calvert | 38 39 39 N | 076 37 11 W |
| Aqua-Land Airport (historical) | Airport | 7 | Charles | 38 22 00 N | 076 58 23 W |
| Aqua-Land Marina | Locale | 0 | Charles | 38 21 58 N | 076 58 59 W |
| Aquahart Manor | Populated Place | 19 | Anne Arundel | 39 09 00 N | 076 37 40 W |
| Aquasco | Populated Place | 51 | Prince George's | 38 35 06 N | 076 43 30 W |
| Aquasco Post Office | Post Office | 49 | Prince George's | 38 34 51 N | 076 43 28 W |
| Aquasco Speedway | Locale | 35 | Prince George's | 38 33 32 N | 076 42 44 W |
| Aquila Scott Park | Park | 87 | Harford | 39 32 11 N | 076 19 44 W |
| Araby United Methodist Church | Church | 97 | Frederick | 39 21 35 N | 077 23 14 W |
| Araby View | Populated Place | 122 | Frederick | 39 21 14 N | 077 23 08 W |
| Arbor Greene | Populated Place | 49 | Calvert | 38 41 28 N | 076 37 52 W |
| Arboranda Estates | Populated Place | 144 | Washington | 39 41 00 N | 077 47 19 W |
| Arbordale | Populated Place | 19 | Anne Arundel | 39 08 43 N | 076 36 59 W |
| Arboretum | Locale | | Allegany | 39 38 55 N | 078 56 17 W |
| Arborview | Populated Place | 50 | Charles | 38 29 50 N | 076 46 57 W |
| Arborwood | Populated Place | 211 | Baltimore | 39 27 50 N | 076 47 28 W |
| Arbour Green | Populated Place | 65 | Baltimore | 39 23 55 N | 076 27 24 W |
| Arbour Manor | Populated Place | 42 | Baltimore | 39 14 35 N | 076 41 58 W |
| Arbutus | Populated Place | 46 | Baltimore | 39 15 16 N | 076 42 00 W |
| Arbutus Branch Baltimore County Public Library | Building | 30 | Baltimore | 39 14 58 N | 076 41 19 W |
| Arbutus Elementary School | School | 29 | Baltimore | 39 14 51 N | 076 41 48 W |
| Arbutus Memorial Park Cemetery | Cemetery | 49 | Baltimore | 39 14 41 N | 076 42 25 W |
| Arbutus Middle School | School | 44 | Baltimore | 39 14 53 N | 076 42 20 W |
| Arbutus Plaza Shopping Center | Locale | 55 | Baltimore | 39 15 40 N | 076 41 45 W |
| Arbutus United Methodist Church | Church | 23 | Baltimore | 39 14 59 N | 076 41 34 W |
| Arbutus Volunteer Fire Department Station 35 | Building | | Baltimore | 39 15 01 N | 076 41 31 W |
| Arcadia | Populated Place | 10 | Anne Arundel | 39 05 45 N | 076 25 44 W |
| Arcadia Shores | Populated Place | 3 | Talbot | 38 45 50 N | 076 09 38 W |
| Arcadia Volunteer Fire Company Station 43 | Building | | Baltimore | 39 56 35 N | 077 23 56 W |
| Arch Bridge | Populated Place | 321 | Frederick | 39 26 52 N | 077 30 03 W |
| Archbishop Curley High School | School | 42 | Baltimore (city) | 39 18 46 N | 076 33 55 W |
| Archbishop Keough High School | School | 36 | Baltimore (city) | 39 16 07 N | 076 39 59 W |
| Archbishop Neale School | School | 44 | Charles | 38 31 42 N | 076 59 12 W |
| Arched Bow Valley | Populated Place | 236 | Carroll | 39 37 24 N | 076 49 50 W |
| Arcola | Populated Place | 137 | Montgomery | 39 02 52 N | 077 03 06 W |
| Arcola School | School | 120 | Montgomery | 39 02 42 N | 077 02 22 W |
| Arctic Park | Park | 96 | Montgomery | 39 04 41 N | 077 05 54 W |
| Arden on the Severn | Populated Place | 15 | Anne Arundel | 39 03 57 N | 076 34 44 W |
| Arden Park | Park | 23 | Anne Arundel | 39 03 46 N | 076 35 29 W |
| Arden Pond | Lake | 4 | Anne Arundel | 39 04 00 N | 076 34 48 W |
| Arden Station | Locale | 6 | Somerset | 38 08 13 N | 075 39 34 W |
| Arden Valley | Populated Place | 200 | Baltimore | 39 34 25 N | 076 41 19 W |
| Ardmore | Populated Place | 42 | Prince George's | 38 56 00 N | 076 51 07 W |
| Ardmore Elementary School | School | 57 | Prince George's | 38 55 57 N | 076 50 48 W |
| Ardwick | Populated Place | 49 | Prince George's | 38 56 44 N | 076 52 51 W |
| Ardwick Industrial Center | Locale | 26 | Prince George's | 38 56 35 N | 076 52 08 W |
| Ardwick Industrial Park | Locale | 18 | Prince George's | 38 56 09 N | 076 52 57 W |
| Ardwick Park | Populated Place | 32 | Prince George's | 38 56 31 N | 076 52 18 W |
| Area 1 School Administration Center | Building | 114 | Montgomery | 39 02 31 N | 077 06 48 W |
| Area 3 School Administration Center | Building | 145 | Montgomery | 39 10 40 N | 077 16 08 W |
| Arena Plaza Shopping Center | Locale | 49 | Prince George's | 38 54 57 N | 076 51 30 W |
| Argonne Hills | Populated Place | 60 | Anne Arundel | 39 06 52 N | 076 45 55 W |
| Argyle Community Building | Building | 101 | Montgomery | 39 01 05 N | 077 01 41 W |
| Argyle Country Club | Locale | 129 | Montgomery | 39 05 51 N | 077 02 59 W |
| Argyle Middle School | School | 124 | Montgomery | 39 05 26 N | 077 02 53 W |
| Argyle Park | Park | 105 | Montgomery | 39 01 02 N | 077 01 43 W |