List of highway route numbers in Oregon Mainline routes Mainline routes

| Number_ | South_west_end | North_east_end | Formed | Eliminated_ |
|---|---|---|---|---|
| Oregon Route 8 | OR 6 near Gales Creek | US 26 east of Beaverton | 1936 |  |
| Oregon Route 10 | OR 219 south of Hillsboro | US 26 in Portland | 1932 |  |
| Oregon Route 11 | I-84 near Pendleton | WA 125 towards Walla Walla, WA | 1932 |  |
| Oregon Route 14 | US 101 at Hebo | OR 18 west of Willamina | 1932 | 1950s |
| Oregon Route 15 | US 30 in Pendleton | US 730 at Cold Springs | 1932 | 1934 |
| Oregon Route 18 | US 101 west of Otis Junction | OR 99W north of Dayton | 1932 |  |
| Oregon Route 18 Business | OR 18 at Wallace Bridge | OR 18 east of Sheridan | 1960 |  |
| Oregon Route 19 | US 26 northwest of Dayville | I-84/US 30 in Arlington | 1932 |  |