| Business | Phone |
| Shannon & Wilson Inc 2255 Sw Canyon Rd, Portland 97201 | (503) 223-6147 |
| Redmond & Assoc 3537 Se 144th Ave, Portland 97236 | (503) 760-1060 |
| Pacrim Geotechinical 506 Sw 6th Ave # 1006, Portland 97204 | (503) 239-3941 |
| Foster Gambee Geotechnical Pc 14355 Nw Mcnamee Rd, Portland 97231 | (503) 621-1233 |
| Golder Associates Inc 4445 Sw Barbur Blvd # 101, Portland 97239 | (503) 241-9404 |
| La Vielle Geotechnical 2313 Ne Alameda St, Portland 97212 | (503) 287-0511 |
| Geo Design Inc 15575 Sw Sequoia Pkwy # 100, Portland 97224 | (503) 968-8787 |