US-395
(Cold Springs Jct. to the Washington Border; MP 193.46-203.28, 9.82 miles)
Columbia Blvd./Columbia Ln. (Morrow County)
(Boardman to Irrigon)
S Main St./S Main Ave.
(within Irrigon)
US-730
(Irrigon to the Washington Border)
US-12 has never officially entered the state of Oregon, but according to US-Highways.com, there was possibly a 1962 plan to extend US-12 all the way into Boardman; it had been extended to Lewiston, Idaho, the same year. If it had extended inward, it would've completely overtaken the US-730 routing in Oregon and Washington, effectively retiring it. Other plans included extending it to Pasco, Washington and Vancouver, Washington. The latter would've most likely (although I am not entirely sure as to the exact routing) been routed along Washington's PSH-8 from Vancouver to Maryhill (already designated a part of US-830) and the PSH-8 Maryhill-Kennewick Branch. Vancouver's routing bit the dust, and Pasco, Washington is now a major city along US-12's current route, which ends at the coastal city of Aberdeen, Washington and follows the old US-410. Most of what would've been US-12 is now US-730, but US-730's route was realigned in 1966 (see my US-730 page for that information.)