Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Oregon Electric Right of Way Path | Park | 91 | Washington | 45 28 03 N | 122 45 11 W |
| Oregon End Dam | Dam | 1393 | Harney | 42 02 60 N | 118 48 04 W |
| Oregon End Ranch | Locale | 1379 | Harney | 42 02 34 N | 118 48 08 W |
| Oregon End Reservoir | Reservoir | 1393 | Harney | 42 02 60 N | 118 48 04 W |
| Oregon End Table | Summit | 1639 | Harney | 42 02 52 N | 118 49 13 W |
| Oregon End Well | Well | 1346 | Harney | 42 00 24 N | 118 48 44 W |
| Oregon Episcopal School | School | 84 | Washington | 45 28 27 N | 122 45 19 W |
| Oregon Fibre Products Dam Number One | Dam | 507 | Umatilla | 45 30 11 N | 118 50 16 W |
| Oregon Gulch | Valley | | Grant | 44 52 10 N | 118 35 13 W |
| Oregon Gulch | Valley | | Jackson | 42 03 26 N | 122 21 33 W |
| Oregon Gulch Camp | Locale | 1588 | Grant | 44 52 26 N | 118 37 01 W |
| Oregon Gulch Reservoir Number One | Reservoir | 1032 | Jackson | 42 03 35 N | 122 22 29 W |
| Oregon Health Sciences University | School | 162 | Multnomah | 45 30 02 N | 122 41 07 W |
| Oregon Health Sciences University Heliport | Airport | 166 | Multnomah | 45 29 44 N | 122 41 14 W |
| Oregon Health Sciences University School of Dentistry | School | 95 | Multnomah | 45 29 55 N | 122 40 59 W |
| Oregon Hill | Summit | 1592 | Malheur | 42 16 49 N | 117 07 26 W |
| Oregon Hill Reservoir | Reservoir | 1583 | Malheur | 42 16 51 N | 117 07 08 W |
| Oregon Historical Society Museum and Research Library | Building | 35 | Multnomah | 45 30 57 N | 122 40 57 W |
| Oregon Institute of Marine Biology | School | 23 | Coos | 43 20 41 N | 124 19 49 W |
| Oregon Institute of Technology | School | 1324 | Klamath | 42 15 25 N | 121 47 09 W |
| Oregon Island | Island | 550 | Baker | 44 51 25 N | 116 53 24 W |
| Oregon Islands National Wildlife Refuge | Park | -9 | Lane | 44 10 59 N | 124 07 19 W |
| Oregon Islands Wilderness | Reserve | -9 | Lane | 44 10 59 N | 124 07 19 W |
| Oregon King Mine | Mine | 812 | Jefferson | 44 45 17 N | 120 44 29 W |
| Oregon Lake | Lake | 1588 | Malheur | 42 18 44 N | 117 01 42 W |
| Oregon Lake Creek | Stream | | Malheur | 42 20 45 N | 117 03 22 W |
| Oregon Lake Creek Reservoir | Reservoir | 1568 | Malheur | 42 20 01 N | 117 04 10 W |
| Oregon Lake Reservoir | Reservoir | 1601 | Malheur | 42 17 40 N | 117 01 47 W |
| Oregon Mine | Mine | 1558 | Grant | 44 17 28 N | 119 17 42 W |
| Oregon Mine Camp | Locale | 1317 | Grant | 44 16 30 N | 119 17 48 W |
| Oregon Mine Creek | Stream | | Grant | 44 16 35 N | 119 17 58 W |
| Oregon Mine Recreation Site | Locale | 1340 | Grant | 44 16 28 N | 119 17 48 W |
| Oregon Mountain | Summit | 1064 | Josephine | 42 00 05 N | 123 47 53 W |
| Oregon Museum of Science and Industry | Building | 8 | Multnomah | 45 30 30 N | 122 39 59 W |
| Oregon Park | Park | 46 | Multnomah | 45 31 37 N | 122 38 10 W |
| Oregon Recreation Site | Locale | 1521 | Baker | 44 32 49 N | 118 20 31 W |
| Oregon Sky Ranch | Airport | 407 | Umatilla | 45 52 44 N | 118 24 19 W |
| Oregon Slope | Area | 699 | Malheur | 44 08 49 N | 116 58 20 W |
| Oregon Slope | Locale | 668 | Malheur | 44 09 20 N | 116 56 39 W |
| Oregon Slope Community Hall | Locale | 664 | Malheur | 44 09 16 N | 116 56 15 W |
| Oregon Spring | Spring | 1789 | Lake | 42 30 57 N | 120 01 34 W |
| Oregon State Capitol | Building | 51 | Marion | 44 56 19 N | 123 01 48 W |
| Oregon State Correctional Institution | Locale | 79 | Marion | 44 53 51 N | 122 56 56 W |
| Oregon State Correctional Institution Office | Building | 83 | Marion | 44 52 38 N | 122 58 25 W |
| Oregon State Fairgrounds | Park | 52 | Marion | 44 57 32 N | 123 00 33 W |
| Oregon State Fish Hatchery | Locale | 84 | Lincoln | 44 43 09 N | 123 42 38 W |
| Oregon State Fish Hatchery | Locale | 53 | Marion | 45 10 14 N | 122 59 24 W |
| Oregon State Forestry District Headquarters | Locale | 14 | Clatsop | 46 09 07 N | 123 47 40 W |
| Oregon State Forestry District Headquarters | Locale | 895 | Crook | 44 18 15 N | 120 48 26 W |
| Oregon State Game Commission Regional Headquarters | Locale | 96 | Benton | 44 40 07 N | 123 13 14 W |
| Oregon State Mental Hospital | Hospital | 63 | Marion | 44 56 19 N | 123 00 09 W |
| Oregon State Penitentiary | Locale | 58 | Marion | 44 55 58 N | 123 00 11 W |
| Oregon State School for the Deaf | School | 48 | Marion | 44 57 53 N | 123 01 11 W |
| Oregon State University | School | 79 | Benton | 44 34 02 N | 123 16 41 W |
| Oregon State University Agricultural Experiment Station | Locale | 93 | Linn | 44 32 43 N | 122 59 04 W |
| Oregon State University Agricultural Experiment Station | Locale | 459 | Umatilla | 45 43 01 N | 118 37 39 W |
| Oregon State University Agriculture Experiment StatiON | School | 193 | Umatilla | 45 48 58 N | 119 16 57 W |
| Oregon State University Experimental Farm | Locale | 67 | Linn | 44 34 03 N | 123 14 42 W |
| Oregon State University Experimental Station | School | 50 | Clackamas | 45 16 50 N | 122 44 55 W |
| Oregon State University Marine Science Center | School | 5 | Lincoln | 44 37 09 N | 124 02 44 W |
| Oregon State University Test Field Laborator | School | 71 | Benton | 44 37 58 N | 123 11 36 W |
| Oregon Technical Institute | School | 1464 | Klamath | 42 15 45 N | 121 44 37 W |
| Oregon Tourism Safety Rest Area (historical) | Locale | 781 | Jackson | 42 07 59 N | 122 37 54 W |
| Oregon Trail | Trail | 281 | Baker | 45 37 39 N | 120 02 15 W |
| Oregon Trail Arboretum | Park | 201 | Umatilla | 45 44 27 N | 119 11 12 W |
| Oregon Trail City Park | Park | 56 | Washington | 45 22 11 N | 122 51 42 W |
| Oregon Trail Historical Monument | Park | 1127 | Baker | 44 48 39 N | 117 44 38 W |
| Oregon Trail Interpretive Park | Locale | 1181 | Union | 45 23 56 N | 118 19 05 W |
| Oregon Trail Monument | Park | 1037 | Baker | 44 48 19 N | 117 50 60 W |
| Oregon Trunk Junction | Locale | 51 | Wasco | 45 38 41 N | 120 59 08 W |
| Oregon Women's Correctional Center | Locale | 57 | Marion | 44 55 49 N | 123 00 11 W |
| Oregon Yacht Club | Locale | 4 | Multnomah | 45 28 27 N | 122 39 43 W |
| Oregon Zoo | Park | 192 | Multnomah | 45 30 31 N | 122 42 47 W |
| Oreida Spring | Spring | 1221 | Malheur | 43 17 50 N | 117 01 42 W |
| Orejana Basin Waterhole | Reservoir | 1602 | Harney | 42 55 45 N | 119 28 59 W |
| Orejana Canyon | Valley | | Harney | 42 48 48 N | 119 30 47 W |
| Orejana Flat | Flat | 1648 | Harney | 43 00 37 N | 118 22 30 W |
| Orejana Rim | Cliff | 1465 | Harney | 42 51 15 N | 119 29 45 W |
| Orejana Waterhole | Reservoir | 1585 | Harney | 42 56 10 N | 119 28 09 W |
| Oremite Mine | Mine | 785 | Deschutes | 44 21 21 N | 121 17 40 W |
| Orenco | Populated Place | 57 | Washington | 45 31 39 N | 122 54 43 W |
| Orenco Post Office (historical) | Post Office | 57 | Washington | 45 31 39 N | 122 54 43 W |
| Orenco Woods Golf Course | Locale | 56 | Washington | 45 31 38 N | 122 54 17 W |
| Oreoil (historical) | Locale | 1258 | Klamath | 42 14 05 N | 121 30 14 W |
| Oretech Post Office | Post Office | 1464 | Klamath | 42 15 45 N | 121 44 37 W |
| Oretown | Populated Place | 10 | Tillamook | 45 09 13 N | 123 57 19 W |
| Oretown Cemetery | Cemetery | 62 | Tillamook | 45 09 12 N | 123 56 55 W |
| Oretown Post Office (historical) | Post Office | 10 | Tillamook | 45 09 13 N | 123 57 19 W |
| Orford Reef | Bar | 3 | Curry | 42 47 06 N | 124 36 53 W |
| Oriana Corrals | Locale | 1655 | Klamath | 42 13 40 N | 120 59 57 W |
| Oriana Creek | Stream | | Harney | 43 01 25 N | 118 20 14 W |
| Oriana Dam | Dam | 1822 | Harney | 42 06 12 N | 118 23 16 W |
| Oriana Reservoir | Reservoir | 1822 | Harney | 42 06 12 N | 118 23 16 W |
| Oriano Spring | Spring | 1054 | Malheur | 43 23 26 N | 117 28 44 W |
| Orient | Populated Place | 169 | Multnomah | 45 28 02 N | 122 21 09 W |
| Orient Post Office (historical) | Post Office | 169 | Multnomah | 45 28 02 N | 122 21 09 W |
| Oriental Basin | Basin | 1493 | Umatilla | 45 00 46 N | 118 43 03 W |
| Oriental Creek | Stream | | Grant | 44 58 33 N | 118 43 42 W |
| Oriental Creek Recreation Site | Locale | 979 | Grant | 44 58 27 N | 118 43 39 W |
| Oriole Mine | Mine | 452 | Josephine | 42 35 28 N | 123 36 34 W |
| Orion Mine | Mine | 1559 | Baker | 44 22 40 N | 118 16 51 W |
| Ork Reef | Bar | 2 | Douglas | 43 41 02 N | 124 10 59 W |
| Orleans | Locale | 71 | Linn | 44 34 12 N | 123 11 26 W |
| Orleans Cemetery | Cemetery | 72 | Linn | 44 34 09 N | 123 11 29 W |
| Orman Spring | Spring | 1044 | Baker | 44 40 34 N | 117 28 41 W |
| Ornoname 10 Dam | Dam | 109 | Marion | 44 48 53 N | 123 01 58 W |
| Ornoname 11 Dam | Dam | 164 | Douglas | 43 05 23 N | 123 25 04 W |
| Ornoname 12 Dam | Dam | 152 | Douglas | 43 09 47 N | 123 22 16 W |
| Ornoname 13 Dam | Dam | 49 | Washington | 45 34 05 N | 123 05 53 W |
| Ornoname 14 Dam | Dam | 86 | Benton | 44 33 53 N | 123 18 52 W |