| Stone & Webster Engineering | Portland | OR |
| Stoney Creek | Portland | OR |
| Stony Creek | Portland | OR |
| Stony Point | Portland | OR |
| Strombo | Portland | OR |
| Suburban Pools | Forest Grove | OR |
| Sully's Hill | Portland | OR |
| Sunrise Utility | Bend | OR |
| Sunset | Portland | OR |
| Superior Lumber | Glendale | OR |
| Superior Troy Laundry | Klamath Falls | OR |
| Surface Combustion | Portland | OR |
| Sutherlin Plywood | Sutherlin | OR |
| Swan Island Shipyard | Portland | OR |
| Swimming Pool | Portland | OR |
| Table Rock | Portland | OR |
| Tailee | Portland | OR |
| Tanker Northfield | Portland | OR |
| Teachers Credit Union Building | Eugene | OR |
| Teamsters Building | Portland | OR |
| Teeples & Thatcher | Portland | OR |
| Tektronix | Beaverton | OR |
| Teledyne Wah Chang | Albany | OR |
| Temple Victory | Portland | OR |
| Terminal Ice & Cold Storage | Woodburn | OR |
| Terminal Ice & Cold Storage | Salem | OR |
| Terminal Transfer | Portland | OR |
| Texaco | Portland | OR |
| Thallepus | Portland | OR |
| Thalmus | Portland | OR |
| Thaumastus | Portland | OR |
| The Dalles | Portland | OR |
| Thelidomus | Portland | OR |
| Theobaldius | Portland | OR |
| Theodoxus | Portland | OR |
| Thermoseal | Portland | OR |
| Thomas A. Edison | Portland | OR |
| Thomas Condon | Portland | OR |
| Thomas Crawford | Portland | OR |
| Thomas Jefferson | Portland | OR |
| Thomas McDonough | Portland | OR |
| Thomas Nuttall | Portland | OR |
| Thomas W Symons | Portland | OR |
| Tigard Convalescent Home | Tigard | OR |
| Tillamook | Portland | OR |
| Tillamook County General Hospital | Tillamook | OR |
| Timber Products Mill | Medford | OR |
| Tomacacori | Portland | OR |
| Tomocyclus | Portland | OR |
| Tomogerus | Portland | OR |
