| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| O'BLENESS MEMORIAL HOSPITAL | airport | United States | 39.33 | -82.11 | 720 | 0 | |
| O'BRIEN AIRPARK | airport | United States | 32.49 | -96.85 | 650 | 0 | |
| O'BRIEN AIRPARK EAST/WEST | airport | United States | 30.05 | -82.98 | 55 | 0 | |
| O'BRIEN FLYING SERVICE | airport | United States | 30.22 | -93.00 | 26 | 0 | |
| O'Banion Mobile Home Park | city | Arizona | United States | 33.37 | -110.76 | 4189 | |
| O'Bannon | city | Kentucky | United States | 38.29 | -85.51 | 830 | |
| O'Brien | city | Florida | United States | 30.04 | -82.94 | 59 | |
| O'Brien | city | Kansas | United States | 38.51 | -95.03 | 895 | |
| O'Brien | city | Oregon | United States | 42.07 | -123.70 | 1669 | |
| O'Brien | city | Texas | United States | 33.38 | -99.84 | 1669 | |
| O'Brien | city | Washington | United States | 47.41 | -122.24 | 190 | |
| O'Brien | city | California | United States | 40.81 | -122.32 | 1669 | |
| O'Brien (historical) | city | West Virginia | United States | 39.05 | -80.03 | 1945 | |
| O'Briens Corner | city | Massachusetts | United States | 42.09 | -72.64 | 144 | |
| O'Brion | city | West Virginia | United States | 38.58 | -80.96 | 892 | |
| O'Bryonsville | city | Ohio | United States | 39.13 | -84.46 | 830 | |
| O'CONNOR FIELD | airport | United States | 42.37 | -89.35 | 900 | 0 | |
| O'Canas Family Colonia | city | Texas | United States | 26.22 | -97.83 | 49 | |
| O'Conner | city | Tennessee | United States | 36.02 | -85.51 | 1066 | |
| O'Connor | city | Nebraska | United States | 41.51 | -98.47 | 1975 | |
| O'Connor Point | city | Ohio | United States | 40.50 | -83.85 | 997 | |
| O'Donnell | city | Pennsylvania | United States | 41.10 | -78.94 | 1669 | |
| O'Donnell | city | Texas | United States | 32.96 | -101.83 | 3349 | |
| O'Donnell | city | Maryland | United States | 39.25 | -76.86 | 403 | |
| O'Donnell Bend | city | Arkansas | United States | 35.80 | -89.80 | 236 | |
| O'Donnell Heights | city | Maryland | United States | 39.28 | -76.54 | 29 | |
| O'Donnell Place | city | Texas | United States | 28.45 | -97.33 | 131 | |
| O'Fallon | city | Illinois | United States | 38.59 | -89.91 | 830 | |
| O'Fallon | city | Missouri | United States | 38.81 | -90.70 | 830 | |
| O'Fallon | city | Missouri | United States | 38.67 | -90.23 | 830 | |
| O'Fallons | city | Nebraska | United States | 41.16 | -101.08 | 2919 | |
| O'Farrell | city | Texas | United States | 33.12 | -94.32 | 380 | |
| O'Farrell Acres Number 1 Colonia | city | Texas | United States | 28.02 | -97.49 | 52 | |
| O'Farrell Acres Number 2 Colonia | city | Texas | United States | 28.03 | -97.56 | 52 | |
| O'GARA TECH TRAINING FACILITY | airport | United States | 36.57 | -79.20 | 385 | 0 | |
| O'Hara | city | Florida | United States | 28.01 | -82.23 | 95 | |
| O'Kean | city | Arkansas | United States | 36.17 | -90.81 | 262 | |
| O'Leary | city | Georgia | United States | 32.21 | -81.18 | 3 | |
| O'Leary | city | Iowa | United States | 42.71 | -96.06 | 1669 | |
| O'Neal | city | Arkansas | United States | 35.78 | -91.86 | 291 | |
| O'Neal | city | Alabama | United States | 34.85 | -87.04 | 830 | |
| O'Neal | city | South Carolina | United States | 35.01 | -82.28 | 961 | |
| O'Neal | city | Virginia | United States | 38.35 | -78.27 | 830 | |
| O'Neal Place | city | Louisiana | United States | 30.43 | -91.00 | 22 | |
| O'Neals | city | California | United States | 37.13 | -119.69 | 1669 | |
| O'Neals Crossroad | city | Georgia | United States | 33.19 | -85.22 | 830 | |
| O'Neil | city | Florida | United States | 30.62 | -81.51 | 13 | |
| O'Neil | city | Mississippi | United States | 31.30 | -90.88 | 396 | |
| O'Neil | city | Michigan | United States | 44.64 | -85.07 | 1122 | |
| O'Neil (historical) | city | Nevada | United States | 41.78 | -115.02 | 5869 | |
| O'Neil Corners | city | Oregon | United States | 45.27 | -122.66 | 180 | |
| O'Neil Landing | city | New Mexico | United States | 35.87 | -106.80 | 8389 | |
| O'Neil Place | city | California | United States | 39.70 | -122.96 | 4550 | |
| O'Neill | city | Iowa | United States | 42.61 | -90.89 | 853 | |
| O'Neill | city | Nebraska | United States | 42.46 | -98.65 | 1998 | |
| O'Neill | city | Utah | United States | 41.21 | -111.94 | 5052 | |
| O'Neill | city | West Virginia | United States | 39.29 | -80.41 | 1197 | |
| O'Quinn | city | Texas | United States | 29.82 | -96.97 | 406 | |
| O'RILEY | airport | United States | 42.98 | -74.73 | 700 | 0 | |
| O'Reilly | city | Mississippi | United States | 33.67 | -90.73 | 134 | |
| O'Reily Estates | city | Georgia | United States | 32.71 | -83.63 | 301 | |
| O'Ryans Point on Half Moon Lake | city | Florida | United States | 28.10 | -82.55 | 45 | |
| O'SULLIVAN AHP | airport | United States | 35.33 | -120.73 | 250 | 0 | |
| O'TOOLE RANCH | airport | United States | 39.07 | -117.42 | 6520 | 0 |