| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Robbins | city | Maryland | United States | 38.38 | -76.08 | 3 | |
| Robbins Landing | city | Maryland | United States | 38.38 | -76.06 | 3 | |
| Roberts | city | Maryland | United States | 39.12 | -75.92 | 49 | |
| Roberts | city | Maryland | United States | 39.63 | -78.80 | 698 | |
| Roberts Field | city | Maryland | United States | 39.60 | -76.84 | 800 | |
| Roberts Mill Run | city | Maryland | United States | 39.66 | -77.16 | 528 | |
| Roberts Retreat | city | Maryland | United States | 39.41 | -77.49 | 462 | |
| Robeys Farmlets | city | Maryland | United States | 39.09 | -76.88 | 249 | |
| Robie Manor | city | Maryland | United States | 38.60 | -77.01 | 147 | |
| Robin Acres | city | Maryland | United States | 39.62 | -76.07 | 400 | |
| Robin Hood Hill | city | Maryland | United States | 39.03 | -76.54 | 16 | |
| Robin Hood Manor | city | Maryland | United States | 39.54 | -76.14 | 95 | |
| Robin Meadows | city | Maryland | United States | 39.37 | -77.43 | 298 | |
| Robindale | city | Maryland | United States | 39.06 | -77.09 | 275 | |
| Robindell Heights | city | Maryland | United States | 39.41 | -77.15 | 649 | |
| Robinson | city | Maryland | United States | 39.08 | -76.55 | 6 | |
| Robinson Corner | city | Maryland | United States | 39.29 | -76.01 | 49 | |
| Robinsons Promise | city | Maryland | United States | 39.13 | -76.84 | 249 | |
| Robinwood | city | Maryland | United States | 39.64 | -77.66 | 606 | |
| Robinwood | city | Maryland | United States | 38.95 | -76.51 | 22 | |
| Roblee Acres | city | Maryland | United States | 38.82 | -76.81 | 147 | |
| Robshire Manor | city | Maryland | United States | 38.58 | -76.60 | 49 | |
| Rochelle Meadows | city | Maryland | United States | 39.52 | -76.42 | 469 | |
| Rock | city | Maryland | United States | 39.63 | -76.14 | 49 | |
| Rock Acres | city | Maryland | United States | 39.61 | -76.40 | 416 | |
| Rock Anna | city | Maryland | United States | 39.14 | -76.51 | 59 | |
| Rock Chapel Estates | city | Maryland | United States | 39.50 | -77.36 | 298 | |
| Rock Creek Estates | city | Maryland | United States | 39.43 | -77.43 | 301 | |
| Rock Creek Estates | city | Maryland | United States | 39.16 | -76.51 | 0 | |
| Rock Creek Forest | city | Maryland | United States | 38.99 | -77.06 | 200 | |
| Rock Creek Gardens | city | Maryland | United States | 38.99 | -77.05 | 209 | |
| Rock Creek Hills | city | Maryland | United States | 39.01 | -77.07 | 209 | |
| Rock Creek Knolls | city | Maryland | United States | 39.00 | -77.07 | 196 | |
| Rock Creek Landing | city | Maryland | United States | 39.14 | -76.53 | 85 | |
| Rock Creek Palisades | city | Maryland | United States | 39.04 | -77.08 | 295 | |
| Rock Creek Park | city | Maryland | United States | 39.15 | -76.49 | 55 | |
| Rock Creek Village | city | Maryland | United States | 39.08 | -77.10 | 347 | |
| Rock Hall | city | Maryland | United States | 39.27 | -77.53 | 249 | |
| Rock Hall | city | Maryland | United States | 39.14 | -76.23 | 3 | |
| Rock Hill Beach | city | Maryland | United States | 39.15 | -76.52 | 3 | |
| Rock Manor | city | Maryland | United States | 39.66 | -76.25 | 351 | |
| Rock Point | city | Maryland | United States | 38.27 | -76.84 | 3 | |
| Rock Run | city | Maryland | United States | 39.61 | -76.14 | 49 | |
| Rock Run | city | Maryland | United States | 39.61 | -76.12 | 75 | |
| Rock Run Estates | city | Maryland | United States | 39.63 | -76.13 | 314 | |
| Rock Spring | city | Maryland | United States | 39.57 | -76.38 | 479 | |
| Rock Springs | city | Maryland | United States | 39.72 | -76.16 | 462 | |
| Rockawalking Acres | city | Maryland | United States | 38.38 | -75.68 | 26 | |
| Rockawalking Estates | city | Maryland | United States | 38.36 | -75.68 | 19 | |
| Rockawalking Village | city | Maryland | United States | 38.39 | -75.67 | 32 | |
| Rockaway Beach | city | Maryland | United States | 39.29 | -76.40 | 3 | |
| Rockbrook Trailer Park | city | Maryland | United States | 39.64 | -76.83 | 751 | |
| Rockbrook Village | city | Maryland | United States | 39.64 | -76.83 | 751 | |
| Rockburn Commons | city | Maryland | United States | 39.21 | -76.73 | 180 | |
| Rockcrest | city | Maryland | United States | 39.08 | -77.13 | 400 | |
| Rockdale | city | Maryland | United States | 39.68 | -76.77 | 744 | |
| Rockdale | city | Maryland | United States | 39.36 | -76.77 | 498 | |
| Rockdale | city | Maryland | United States | 39.70 | -77.84 | 459 | |
| Rockdale Manor | city | Maryland | United States | 39.53 | -76.41 | 387 | |
| Rockhill Beach | city | Maryland | United States | 39.14 | -76.52 | 45 | |
| Rockland | city | Maryland | United States | 39.30 | -76.81 | 449 | |
| Rockland | city | Maryland | United States | 39.40 | -76.67 | 298 | |
| Rockland | city | Maryland | United States | 39.07 | -77.13 | 357 | |
| Rockland Estates | city | Maryland | United States | 39.58 | -77.05 | 603 | |
| Rockland Run | city | Maryland | United States | 39.39 | -76.67 | 400 | |
| Rockridge Forest | city | Maryland | United States | 39.65 | -76.38 | 479 | |
| Rockview Beach | city | Maryland | United States | 39.14 | -76.51 | 49 | |
| Rockville | city | Maryland | United States | 39.08 | -77.15 | 400 | |
| Rockwell | city | Maryland | United States | 39.28 | -76.78 | 449 | |
| Rockwood Beach | city | Maryland | United States | 39.16 | -76.48 | 39 | |
| Rocky Acres | city | Maryland | United States | 39.06 | -76.91 | 147 | |
| Rocky Acres | city | Maryland | United States | 39.47 | -76.94 | 613 | |
| Rocky Brook Park | city | Maryland | United States | 39.05 | -77.00 | 396 | |
| Rocky Forge | city | Maryland | United States | 39.72 | -77.60 | 613 | |
| Rocky Gorge Estates | city | Maryland | United States | 39.11 | -76.89 | 265 | |
| Rocky Gorge Meadows | city | Maryland | United States | 39.14 | -76.97 | 337 | |
| Rocky Hook | city | Maryland | United States | 38.48 | -75.93 | 9 | |
| Rocky Ridge | city | Maryland | United States | 39.61 | -77.32 | 393 | |
| Rocky Ridge Estates | city | Maryland | United States | 39.61 | -77.30 | 305 | |
| Rocky Road Park | city | Maryland | United States | 39.24 | -77.17 | 498 | |
| Rocky Springs | city | Maryland | United States | 39.45 | -77.45 | 400 | |
| Roddy (historical) | city | Maryland | United States | 39.64 | -77.40 | 472 | |
| Rodgers Forge | city | Maryland | United States | 39.38 | -76.61 | 419 | |
| Rodo Beach | city | Maryland | United States | 38.08 | -76.33 | 3 | |
| Roe | city | Maryland | United States | 39.06 | -75.92 | 49 | |
| Roelkeys Knoll | city | Maryland | United States | 39.34 | -77.66 | 436 | |
| Rogers (historical) | city | Maryland | United States | 39.41 | -76.69 | 334 | |
| Rogers Heights | city | Maryland | United States | 38.95 | -76.92 | 180 | |
| Rogers Mill | city | Maryland | United States | 38.49 | -76.93 | 49 | |
| Rognel Heights | city | Maryland | United States | 39.29 | -76.69 | 200 | |
| Rohrersville | city | Maryland | United States | 39.43 | -77.66 | 705 | |
| Rohrersville Station | city | Maryland | United States | 39.43 | -77.68 | 685 | |
| Rol-Park Trailer Village | city | Maryland | United States | 39.12 | -76.64 | 91 | |
| Roland Heights | city | Maryland | United States | 39.54 | -76.36 | 344 | |
| Roland Park | city | Maryland | United States | 39.35 | -76.63 | 344 | |
| Roland Place | city | Maryland | United States | 39.54 | -76.36 | 370 | |
| Roland Terrace | city | Maryland | United States | 39.22 | -76.60 | 49 | |
| Rolee Estates | city | Maryland | United States | 38.74 | -76.94 | 196 | |
| Roller | city | Maryland | United States | 39.70 | -76.81 | 636 | |
| Rolles Beach | city | Maryland | United States | 38.77 | -76.25 | 3 | |
| Rolling Acres | city | Maryland | United States | 38.49 | -76.73 | 98 | |
| Rolling Acres | city | Maryland | United States | 38.61 | -76.55 | 118 | |
| Rolling Acres | city | Maryland | United States | 39.27 | -76.85 | 396 | |
| Rolling Acres | city | Maryland | United States | 38.75 | -76.84 | 196 | |
| Rolling Acres | city | Maryland | United States | 39.06 | -76.97 | 321 | |
| Rolling Carroll Estates | city | Maryland | United States | 39.39 | -77.06 | 748 | |
| Rolling Falls Estates | city | Maryland | United States | 39.66 | -76.81 | 715 | |
| Rolling Glen Farms | city | Maryland | United States | 38.79 | -76.80 | 160 | |
| Rolling Green | city | Maryland | United States | 39.58 | -76.25 | 314 | |
| Rolling Green | city | Maryland | United States | 39.30 | -77.30 | 547 | |
| Rolling Heights | city | Maryland | United States | 39.32 | -76.76 | 449 | |
| Rolling Hills | city | Maryland | United States | 39.35 | -77.19 | 803 | |
| Rolling Hills | city | Maryland | United States | 39.00 | -76.56 | 101 | |
| Rolling Hills | city | Maryland | United States | 39.38 | -77.01 | 567 | |
| Rolling Hills | city | Maryland | United States | 38.22 | -75.47 | 19 | |
| Rolling Hills | city | Maryland | United States | 38.48 | -76.99 | 147 | |
| Rolling Knolls | city | Maryland | United States | 39.64 | -76.50 | 501 | |
| Rolling Knolls | city | Maryland | United States | 39.18 | -77.12 | 498 | |
| Rolling Knolls | city | Maryland | United States | 39.00 | -76.56 | 101 | |
| Rolling Meadows | city | Maryland | United States | 38.36 | -75.68 | 19 | |
| Rolling Park | city | Maryland | United States | 39.35 | -76.77 | 498 | |
| Rolling Ridge | city | Maryland | United States | 39.39 | -76.82 | 593 | |
| Rolling Ridge | city | Maryland | United States | 39.34 | -76.76 | 472 | |
| Rolling Ridge | city | Maryland | United States | 39.31 | -76.80 | 200 | |
| Rolling Ridge | city | Maryland | United States | 39.53 | -77.03 | 728 | |
| Rolling Road Farms | city | Maryland | United States | 39.32 | -76.75 | 400 | |
| Rolling View | city | Maryland | United States | 38.95 | -76.85 | 147 | |
| Rollingwood | city | Maryland | United States | 38.98 | -77.07 | 275 | |
| Rollins Park | city | Maryland | United States | 39.06 | -77.13 | 344 | |
| Rollins View Green | city | Maryland | United States | 39.37 | -76.53 | 275 | |
| Rolph Landing | city | Maryland | United States | 38.90 | -75.95 | 19 | |
| Rolphs | city | Maryland | United States | 39.17 | -76.04 | 36 | |
| Romancoke | city | Maryland | United States | 38.88 | -76.34 | 0 | |
| Romancoke on the Bay | city | Maryland | United States | 38.88 | -76.34 | 3 | |
| Romar Estates | city | Maryland | United States | 38.95 | -76.51 | 6 | |
| Ronalee Hills | city | Maryland | United States | 39.25 | -77.19 | 600 | |
| Roop Mill | city | Maryland | United States | 39.59 | -77.03 | 649 | |
| Roosevelt Heights | city | Maryland | United States | 38.54 | -76.94 | 127 | |
| Rosaryville | city | Maryland | United States | 38.76 | -76.81 | 200 | |
| Rosaryville Estates | city | Maryland | United States | 38.76 | -76.81 | 200 | |
| Rose Haven | city | Maryland | United States | 38.73 | -76.54 | 3 | |
| Rose Hill | city | Maryland | United States | 38.56 | -76.57 | 114 | |
| Rose Hill Estates | city | Maryland | United States | 39.01 | -77.16 | 209 | |
| Rose Mary Estates | city | Maryland | United States | 39.28 | -76.96 | 538 | |
| Rosecroft | city | Maryland | United States | 38.16 | -76.44 | 3 | |
| Rosecroft Park | city | Maryland | United States | 38.80 | -76.97 | 121 | |
| Rosedale | city | Maryland | United States | 39.32 | -76.52 | 39 | |
| Rosedale | city | Maryland | United States | 39.43 | -77.42 | 305 | |
| Rosedale Park | city | Maryland | United States | 39.03 | -76.90 | 91 | |
| Rosedale Park | city | Maryland | United States | 38.99 | -77.09 | 308 | |
| Rosedale Terrace | city | Maryland | United States | 39.31 | -76.51 | 68 | |
| Rosemary Hills | city | Maryland | United States | 39.00 | -77.04 | 301 | |
| Rosemont | city | Maryland | United States | 39.13 | -77.19 | 498 | |
| Rosemont | city | Maryland | United States | 39.33 | -77.62 | 449 | |
| Rosemont | city | Maryland | United States | 39.14 | -76.87 | 347 | |
| Rosemont | city | Maryland | United States | 39.24 | -76.63 | 49 | |
| Roseville Heights | city | Maryland | United States | 39.61 | -76.92 | 846 | |
| Rosewick | city | Maryland | United States | 38.56 | -76.98 | 200 | |
| Rosewood | city | Maryland | United States | 38.52 | -76.54 | 111 | |
| Rosewood Estates | city | Maryland | United States | 39.19 | -77.15 | 554 | |
| Rosewood Forest | city | Maryland | United States | 38.41 | -75.52 | 55 | |
| Roslyn | city | Maryland | United States | 39.37 | -76.74 | 419 | |
| Roslyn Station | city | Maryland | United States | 39.38 | -76.74 | 419 | |
| Ross Acres | city | Maryland | United States | 38.58 | -76.24 | 3 | |
| Ross Cove | city | Maryland | United States | 39.09 | -76.51 | 3 | |
| Ross Farm Woods | city | Maryland | United States | 38.83 | -75.92 | 22 | |
| Ross Run Estates | city | Maryland | United States | 39.64 | -76.93 | 931 | |
| Ross Valley Farms | city | Maryland | United States | 39.57 | -76.66 | 524 | |
| Ross Woods | city | Maryland | United States | 38.45 | -76.55 | 52 | |
| Rossmoor | city | Maryland | United States | 39.10 | -77.07 | 442 | |
| Rossville | city | Maryland | United States | 39.34 | -76.48 | 49 | |
| Rosswood Estates | city | Maryland | United States | 39.50 | -77.27 | 554 | |
| Rosswood Estates | city | Maryland | United States | 39.37 | -77.24 | 547 | |
| Round Acres | city | Maryland | United States | 39.54 | -76.45 | 498 | |
| Round Bay | city | Maryland | United States | 39.06 | -76.54 | 98 | |
| Round Bay View | city | Maryland | United States | 39.06 | -76.54 | 3 | |
| Round Hill | city | Maryland | United States | 39.44 | -77.50 | 1076 | |
| Round View | city | Maryland | United States | 39.00 | -76.46 | 29 | |
| Roundtree | city | Maryland | United States | 39.35 | -77.55 | 495 | |
| Rousby Hall | city | Maryland | United States | 38.33 | -76.45 | 0 | |
| Rover (historical) | city | Maryland | United States | 39.30 | -77.00 | 521 | |
| Rover Mill Estates | city | Maryland | United States | 39.29 | -77.00 | 554 | |
| Rowland Hill | city | Maryland | United States | 39.71 | -77.48 | 1561 | |
| Rowlandsville | city | Maryland | United States | 39.66 | -76.15 | 246 | |
| Rowlandsville Heights | city | Maryland | United States | 39.66 | -76.13 | 170 | |
| Roxbury | city | Maryland | United States | 39.55 | -77.70 | 498 | |
| Roxbury | city | Maryland | United States | 39.26 | -77.05 | 433 | |
| Roxbury Hill | city | Maryland | United States | 39.55 | -77.69 | 488 | |
| Roxbury Mills | city | Maryland | United States | 39.26 | -77.05 | 400 | |
| Royal Acres | city | Maryland | United States | 39.52 | -76.18 | 101 | |
| Royal Acres | city | Maryland | United States | 38.74 | -76.19 | 3 | |
| Royal Beach | city | Maryland | United States | 39.11 | -76.54 | 42 | |
| Royal Heights | city | Maryland | United States | 39.66 | -76.89 | 912 | |
| Royal Heights | city | Maryland | United States | 39.47 | -76.27 | 49 | |
| Royal Oak | city | Maryland | United States | 38.74 | -76.18 | 3 | |
| Royal Oak | city | Maryland | United States | 38.35 | -75.79 | 9 | |
| Royale Gardens | city | Maryland | United States | 38.93 | -76.85 | 196 | |
| Royale Glen | city | Maryland | United States | 38.92 | -76.65 | 98 | |
| Royston Shores | city | Maryland | United States | 39.22 | -76.03 | 3 |