| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Roadamite (historical) | city | California | United States | 34.84 | -120.33 | 830 | |
| Roads End | city | California | United States | 35.93 | -118.50 | 3599 | |
| Rob Roy Junction | city | California | United States | 36.97 | -121.87 | 298 | |
| Robbers Creek | city | California | United States | 40.37 | -121.00 | 5298 | |
| Robbins | city | California | United States | 38.87 | -121.71 | 19 | |
| Robert (historical) | city | California | United States | 37.68 | -122.16 | 9 | |
| Roberts Place | city | California | United States | 40.04 | -121.86 | 1797 | |
| Robertsville | city | California | United States | 37.26 | -121.88 | 170 | |
| Robinson (historical) | city | California | United States | 36.40 | -119.84 | 196 | |
| Robinson Mills | city | California | United States | 39.49 | -121.32 | 2598 | |
| Robinson Ranch | city | California | United States | 33.65 | -117.57 | 1200 | |
| Robinsons Corner | city | California | United States | 39.36 | -121.61 | 98 | |
| Robla | city | California | United States | 38.66 | -121.45 | 36 | |
| Roblar | city | California | United States | 38.32 | -122.76 | 272 | |
| Roble | city | California | United States | 39.66 | -121.81 | 170 | |
| Robles Del Rio | city | California | United States | 36.47 | -121.73 | 830 | |
| Roche | city | California | United States | 36.07 | -119.01 | 830 | |
| Rochedale Village | city | California | United States | 37.87 | -122.26 | 282 | |
| Rochester | city | California | United States | 34.09 | -117.55 | 1102 | |
| Rock City | city | California | United States | 37.85 | -121.94 | 1669 | |
| Rock Creek | city | California | United States | 39.90 | -121.35 | 3349 | |
| Rock Creek Camp | city | California | United States | 39.93 | -121.32 | 2509 | |
| Rock Crest | city | California | United States | 39.93 | -121.32 | 2509 | |
| Rock Haven | city | California | United States | 37.13 | -119.32 | 5869 | |
| Rock Haven (historical) | city | California | United States | 33.00 | -116.97 | 2083 | |
| Rock Springs (historical) | city | California | United States | 35.42 | -118.74 | 2509 | |
| Rockaway Beach | city | California | United States | 37.61 | -122.50 | 242 | |
| Rocking K | city | California | United States | 37.36 | -118.48 | 5029 | |
| Rockland | city | California | United States | 41.98 | -123.96 | 1213 | |
| Rocklin | city | California | United States | 38.79 | -121.24 | 275 | |
| Rockport | city | California | United States | 39.74 | -123.82 | 196 | |
| Rockridge | city | California | United States | 37.84 | -122.25 | 196 | |
| Rocktram | city | California | United States | 38.26 | -122.28 | 3 | |
| Rockville | city | California | United States | 38.24 | -122.12 | 42 | |
| Rockwood | city | California | United States | 33.05 | -115.51 | -1689 | |
| Rocky Hill | city | California | United States | 36.30 | -119.12 | 830 | |
| Rocky Hill | city | California | United States | 38.15 | -120.47 | 2509 | |
| Rodeo | city | California | United States | 38.03 | -122.27 | 19 | |
| Rodgers Crossing | city | California | United States | 36.86 | -119.12 | 1669 | |
| Rodgers Flat | city | California | United States | 39.96 | -121.28 | 2926 | |
| Rodney's Mobile Park | city | California | United States | 41.31 | -122.77 | 3382 | |
| Rogerville | city | California | United States | 39.61 | -121.22 | 3349 | |
| Rohnert Park | city | California | United States | 38.34 | -122.70 | 104 | |
| Rohnerville | city | California | United States | 40.57 | -124.14 | 278 | |
| Rolands | city | California | United States | 38.51 | -122.98 | 396 | |
| Rolinda | city | California | United States | 36.74 | -119.96 | 196 | |
| Rolling Hills | city | California | United States | 33.76 | -118.35 | 1197 | |
| Rolling Hills | city | California | United States | 37.94 | -120.43 | 1669 | |
| Rolling Hills | city | California | United States | 36.90 | -119.80 | 298 | |
| Rolling Hills Estates | city | California | United States | 33.79 | -118.36 | 406 | |
| Rollingwood | city | California | United States | 37.97 | -122.33 | 183 | |
| Roma | city | California | United States | 38.14 | -121.24 | 59 | |
| Romoland | city | California | United States | 33.75 | -117.18 | 1669 | |
| Ronda (historical) | city | California | United States | 38.78 | -121.86 | 55 | |
| Roosevelt | city | California | United States | 34.72 | -118.01 | 2509 | |
| Roosevelt | city | California | United States | 33.86 | -118.30 | 55 | |
| Rosamond | city | California | United States | 34.86 | -118.16 | 2509 | |
| Rose (historical) | city | California | United States | 38.12 | -122.49 | 0 | |
| Rose Hill | city | California | United States | 34.08 | -118.20 | 830 | |
| Rose Park | city | California | United States | 33.78 | -118.16 | 32 | |
| Rose Place | city | California | United States | 39.17 | -122.82 | 3349 | |
| Rosedale | city | California | United States | 35.38 | -119.15 | 377 | |
| Roseland | city | California | United States | 38.42 | -122.73 | 131 | |
| Rosemary | city | California | United States | 34.95 | -120.39 | 396 | |
| Rosemead | city | California | United States | 34.08 | -118.07 | 298 | |
| Rosemont | city | California | United States | 38.55 | -121.36 | 49 | |
| Rosemont | city | California | United States | 33.00 | -116.93 | 1669 | |
| Roseville | city | California | United States | 38.75 | -121.29 | 144 | |
| Roseville | city | California | United States | 32.73 | -117.23 | 22 | |
| Rosewood | city | California | United States | 40.27 | -122.56 | 830 | |
| Rosewood | city | California | United States | 40.77 | -124.17 | 157 | |
| Ross | city | California | United States | 37.96 | -122.56 | 196 | |
| Ross | city | California | United States | 38.46 | -122.89 | 124 | |
| Ross Corner | city | California | United States | 32.78 | -114.59 | 137 | |
| Rossi | city | California | United States | 36.30 | -119.83 | 196 | |
| Rossmoor | city | California | United States | 33.79 | -118.09 | 3 | |
| Rotavele | city | California | United States | 39.68 | -122.00 | 124 | |
| Rough and Ready | city | California | United States | 39.23 | -121.14 | 2509 | |
| Round Mountain | city | California | United States | 40.79 | -121.94 | 2509 | |
| Round Valley | city | California | United States | 37.42 | -118.59 | 5029 | |
| Round Valley (historical) | city | California | United States | 40.12 | -120.97 | 4550 | |
| Roundup Trailer Lodge | city | California | United States | 37.38 | -121.96 | 36 | |
| Routier (historical) | city | California | United States | 38.58 | -121.32 | 68 | |
| Rovana | city | California | United States | 37.41 | -118.62 | 5124 | |
| Rowen | city | California | United States | 35.24 | -118.58 | 2509 | |
| Rowes (historical) | city | California | United States | 39.48 | -123.41 | 2509 | |
| Rowland | city | California | United States | 34.00 | -117.93 | 830 | |
| Rowland Heights | city | California | United States | 33.98 | -117.91 | 830 | |
| Royal Gardens Mobile Home Estates | city | California | United States | 33.74 | -117.95 | 13 | |
| Royal Oak Manufactured Home Community | city | California | United States | 38.54 | -121.73 | 42 | |
| Royal Oak Mobile Home Park | city | California | United States | 33.81 | -118.08 | 3 | |
| Royal Palms | city | California | United States | 33.80 | -116.46 | 291 | |
| Royal Palms Mobile Estates | city | California | United States | 38.67 | -121.75 | 45 | |
| Royal Palms Mobile Home Park | city | California | United States | 34.19 | -119.18 | 3 |