Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Rock Run | Populated Place | 25 | Cecil | 39 36 53 N | 076 07 26 W |
| Rock Run | Populated Place | 16 | Harford | 39 36 29 N | 076 08 35 W |
| Rock Run | Stream | | Cecil | 39 36 49 N | 076 07 37 W |
| Rock Run | Stream | | Harford | 39 36 33 N | 076 08 36 W |
| Rock Run | Stream | | Montgomery | 38 58 11 N | 077 11 04 W |
| Rock Run Cemetery | Cemetery | 125 | Harford | 39 35 33 N | 076 10 06 W |
| Rock Run Church | Church | 123 | Harford | 39 35 30 N | 076 10 09 W |
| Rock Run Culvert | Canal | 15 | Montgomery | 38 58 12 N | 077 10 33 W |
| Rock Run Estates | Populated Place | 77 | Cecil | 39 37 37 N | 076 07 42 W |
| Rock Run Mill | Locale | 16 | Harford | 39 36 29 N | 076 08 35 W |
| Rock Spring | Populated Place | 158 | Harford | 39 34 22 N | 076 23 06 W |
| Rock Spring Church | Church | 153 | Harford | 39 34 27 N | 076 23 15 W |
| Rock Spring Industrial Park | Locale | 89 | Montgomery | 39 01 39 N | 077 09 12 W |
| Rock Spring Shopping Center | Locale | 132 | Harford | 39 33 28 N | 076 22 04 W |
| Rock Springs | Populated Place | 155 | Cecil | 39 42 54 N | 076 09 31 W |
| Rock Springs Swim Club | Locale | 118 | Harford | 39 33 05 N | 076 23 00 W |
| Rock Terrace High School | School | 141 | Montgomery | 39 05 36 N | 077 09 36 W |
| Rock View Elementary School | School | 103 | Montgomery | 39 02 19 N | 077 04 35 W |
| Rockawalkin Community Center | Building | 10 | Wicomico | 38 22 48 N | 075 40 35 W |
| Rockawalking | Locale | 13 | Wicomico | 38 24 08 N | 075 39 36 W |
| Rockawalking Acres | Populated Place | 13 | Wicomico | 38 22 41 N | 075 40 58 W |
| Rockawalking Church | Church | 10 | Wicomico | 38 22 47 N | 075 40 36 W |
| Rockawalking Community Hall | Building | 10 | Wicomico | 38 22 48 N | 075 40 36 W |
| Rockawalking Creek | Stream | | Wicomico | 38 20 27 N | 075 40 47 W |
| Rockawalking Estates | Populated Place | 8 | Wicomico | 38 21 50 N | 075 40 38 W |
| Rockawalking Post Office (historical) | Post Office | 13 | Wicomico | 38 24 07 N | 075 39 39 W |
| Rockawalking Village | Populated Place | 12 | Wicomico | 38 23 30 N | 075 40 17 W |
| Rockaway Beach | Populated Place | 4 | Baltimore | 39 17 41 N | 076 23 57 W |
| Rockbrook Trailer Park | Populated Place | 232 | Carroll | 39 38 15 N | 076 49 56 W |
| Rockburn Branch | Stream | | Howard | 39 13 32 N | 076 43 09 W |
| Rockburn Branch Park | Park | 99 | Howard | 39 13 07 N | 076 45 42 W |
| Rockburn Commons | Populated Place | 63 | Howard | 39 12 24 N | 076 43 59 W |
| Rockburn Elementary School | School | 111 | Howard | 39 12 54 N | 076 46 06 W |
| Rockcrest | Populated Place | 124 | Montgomery | 39 04 32 N | 077 07 50 W |
| Rockcrest Park | Park | 102 | Montgomery | 39 04 26 N | 077 07 24 W |
| Rockdale | Populated Place | 180 | Baltimore | 39 40 51 N | 076 46 05 W |
| Rockdale | Populated Place | 160 | Baltimore | 39 21 22 N | 076 45 56 W |
| Rockdale | Populated Place | 145 | Washington | 39 42 04 N | 077 50 38 W |
| Rockdale Manor | Populated Place | 141 | Harford | 39 31 51 N | 076 24 30 W |
| Rockdale Park | Park | 156 | Baltimore | 39 21 00 N | 076 46 03 W |
| Rockdale Professional Center | Locale | | Baltimore | 39 21 19 N | 076 45 57 W |
| Rockdale Run | Stream | | Washington | 39 42 08 N | 077 49 07 W |
| Rockhill Beach | Populated Place | 9 | Anne Arundel | 39 08 38 N | 076 31 24 W |
| Rockhill School (historical) | School | 182 | Washington | 39 42 11 N | 077 39 41 W |
| Rockhold Creek | Bay | -2 | Anne Arundel | 38 47 19 N | 076 33 20 W |
| Rocking Point | Cape | 1 | Somerset | 37 58 10 N | 076 02 41 W |
| Rocking Point Gut | Gut | -2 | Somerset | 37 58 21 N | 076 02 45 W |
| Rockinghorse Road Elementary School (historical) | School | 97 | Montgomery | 39 03 05 N | 077 05 54 W |
| Rockland | Populated Place | 90 | Baltimore | 39 24 05 N | 076 40 04 W |
| Rockland | Populated Place | 149 | Howard | 39 17 56 N | 076 48 48 W |
| Rockland | Populated Place | 111 | Montgomery | 39 04 21 N | 077 07 35 W |
| Rockland Center School | School | 137 | Howard | 39 17 31 N | 076 48 22 W |
| Rockland Estates | Populated Place | 205 | Carroll | 39 34 42 N | 077 02 43 W |
| Rockland Run | Populated Place | 140 | Baltimore | 39 23 16 N | 076 40 29 W |
| Rockland United Methodist Church | Church | 147 | Howard | 39 18 06 N | 076 49 23 W |
| Rockledge Elementary School | School | 42 | Prince George's | 38 59 48 N | 076 45 28 W |
| Rocklick Creek | Stream | | Garrett | 39 36 48 N | 079 21 39 W |
| Rockmead Park | Park | 104 | Montgomery | 39 04 35 N | 077 10 24 W |
| Rockridge Forest | Populated Place | 147 | Harford | 39 38 59 N | 076 22 58 W |
| Rocks | Locale | 95 | Harford | 39 38 16 N | 076 24 40 W |
| Rockshire Shopping Center | Locale | 119 | Montgomery | 39 04 49 N | 077 11 03 W |
| Rocksprings Post Office (historical) | Post Office | 155 | Cecil | 39 42 55 N | 076 09 30 W |
| Rockview Beach | Populated Place | 7 | Anne Arundel | 39 08 35 N | 076 30 54 W |
| Rockville | Populated Place | 137 | Montgomery | 39 05 02 N | 077 09 10 W |
| Rockville Academy (historical) | School | 134 | Montgomery | 39 04 56 N | 077 09 05 W |
| Rockville Church of Christ | Church | 118 | Montgomery | 39 05 26 N | 077 10 52 W |
| Rockville Church of the Nazarene | Church | 127 | Montgomery | 39 06 46 N | 077 05 29 W |
| Rockville City Hall | Building | 138 | Montgomery | 39 04 54 N | 077 09 07 W |
| Rockville Civic Center | Locale | 125 | Montgomery | 39 05 04 N | 077 07 44 W |
| Rockville Fire Station Company 23 | Building | 121 | Montgomery | 39 03 32 N | 077 07 20 W |
| Rockville Fire Station Company 3 | Building | 132 | Montgomery | 39 05 15 N | 077 09 03 W |
| Rockville Fire Station Company 31 | Building | 125 | Montgomery | 39 07 00 N | 077 15 03 W |
| Rockville Fire Station Company 33 | Building | 122 | Montgomery | 39 02 37 N | 077 11 38 W |
| Rockville Fire Station Training Academy Company 27 | Building | 144 | Montgomery | 39 05 58 N | 077 12 28 W |
| Rockville Free Methodist Church | Church | 130 | Montgomery | 39 04 50 N | 077 08 17 W |
| Rockville Health Center | Hospital | 130 | Montgomery | 39 04 59 N | 077 08 50 W |
| Rockville High School | School | 110 | Montgomery | 39 05 12 N | 077 07 07 W |
| Rockville Library | Building | 132 | Montgomery | 39 04 56 N | 077 09 04 W |
| Rockville Metro Station | Locale | 131 | Montgomery | 39 05 02 N | 077 08 44 W |
| Rockville Police Department District 1 | Building | | Montgomery | 39 07 10 N | 077 16 28 W |
| Rockville Post Office | Post Office | 139 | Montgomery | 39 05 29 N | 077 09 15 W |
| Rockville Railroad Station | Building | 132 | Montgomery | 39 05 04 N | 077 08 48 W |
| Rockville Regional Library | Building | 141 | Montgomery | 39 04 57 N | 077 09 20 W |
| Rockville Senior Center | Building | 138 | Montgomery | 39 06 02 N | 077 10 37 W |
| Rockville United Church | Church | 107 | Montgomery | 39 04 41 N | 077 06 57 W |
| Rockville Water Plant | Locale | 75 | Montgomery | 39 01 18 N | 077 13 56 W |
| Rockville Water Treatment Plant | Locale | 81 | Montgomery | 39 02 25 N | 077 15 14 W |
| Rockwell | Populated Place | 133 | Baltimore | 39 16 38 N | 076 46 34 W |
| Rockwood Beach | Populated Place | 4 | Anne Arundel | 39 09 33 N | 076 29 04 W |
| Rocky Acres | Populated Place | 183 | Carroll | 39 28 22 N | 076 56 13 W |
| Rocky Acres | Populated Place | 59 | Prince George's | 39 03 25 N | 076 54 41 W |
| Rocky Branch | Stream | | Harford | 39 28 59 N | 076 24 05 W |
| Rocky Brook Park | Populated Place | 107 | Montgomery | 39 03 04 N | 076 59 49 W |
| Rocky Forge | Populated Place | 171 | Washington | 39 43 06 N | 077 36 18 W |
| Rocky Fountain Run | Stream | | Frederick | 39 19 55 N | 077 25 20 W |
| Rocky Gap | Gap | 302 | Allegany | 39 41 58 N | 078 40 24 W |
| Rocky Gap Dam | Dam | 366 | Allegany | 39 42 06 N | 078 39 41 W |
| Rocky Gap Run | Stream | | Allegany | 39 42 21 N | 078 41 51 W |
| Rocky Gorge Dam | Dam | 132 | Prince George's | 39 14 00 N | 076 52 29 W |
| Rocky Gorge Driving Range | Locale | 119 | Howard | 39 08 10 N | 076 54 30 W |
| Rocky Gorge Estates | Populated Place | 99 | Prince George's | 39 06 39 N | 076 53 08 W |
| Rocky Gorge Meadows | Populated Place | 126 | Montgomery | 39 08 30 N | 076 58 06 W |
| Rocky Gorge Reservoir | Reservoir | 81 | Prince George's | 39 07 00 N | 076 52 32 W |
| Rocky Hill Branch | Stream | | Frederick | 39 31 38 N | 077 18 00 W |
| Rocky Hill Church | Church | 167 | Frederick | 39 31 50 N | 077 17 17 W |
| Rocky Hill Middle School | School | 169 | Montgomery | 39 13 36 N | 077 15 49 W |
| Rocky Hook | Populated Place | 2 | Dorchester | 38 29 02 N | 075 55 39 W |
| Rocky Islands | Island | 35 | Montgomery | 38 59 38 N | 077 14 54 W |
| Rocky Point | Cape | 1 | Baltimore | 39 14 56 N | 076 24 02 W |
| Rocky Point | Cape | 7 | Calvert | 38 24 50 N | 076 24 55 W |