In the U.S. state of Oregon, U.S. Route 30, a major east-west U.S. Highway, runs from its western terminus in Astoria to the Idaho border east of Ontario, Oregon. West of Portland, US 30 generally follows the southern shore of the Columbia River; east of Portland the highway has largely been replaced with Interstate 84, though it is signed all the way across the state, and diverges from the I-84 mainline in several towns, as a de-facto business route. (The state of Oregon does not sign Interstate business routes; instead it uses the designations US 30 and Oregon Route 99 (along the Interstate 5 corridor) for this purpose.)
1937 sketch including Columbia River Highway (now U.S. Route 30) as it passes west of Sauvie Island, northwest of Portland
The western terminus of US 30 is in Astoria, at an intersection with U.S. Route 101. US 101 southbound from the intersection goes down the length of the Oregon Coast, northbound US 101 crosses the Astoria-Megler Bridge into Washington state. US 30 proceeds east through the intersection, through downtown Astoria, and then along the southern bank of the Columbia.
East of Astoria, US 30 is known as the Lower Columbia River Highway No. 2W (see Oregon highways and routes), a designation which it carries until Portland.
Continuing east, the highway passes through the communities of Woodson and Clatskanie. East of Clatskanie, the highway runs inland from the river a bit, approaching the town of Rainier, Oregon.
Just before Rainer is an interchange providing access to the Lewis and Clark Bridge, which crosses the Columbia to Longview, Washington. After Rainier, the highway turns south, following a bend in the river, and runs parallel to Interstate 5 (which is across the river on the Washington side). Towns along the way include Goble, Deer Island, Columbia City, and St. Helens.
South of St. Helens, US 30 becomes an expressway, known locally as St. Helens Road. The highway proceeds through the towns of Warren, Scappoose, and Burlington (as well as passing by the access road to Sauvie Island) before entering Portland. East of Scappoose is the confluence of the Columbia and Willamette Rivers.
Portland area
In northwest Portland, US 30 is sandwiched between Forest Park on the east and the Willamette River. South of the Linnton area, U.S. Route 30 Bypass heads east across the St. Johns Bridge. US 30 continues south along St. Helens Road, then later on Yeon Avenue through an industrial area as it approaches downtown. On the edge of downtown Portland, US 30 briefly becomes a freeway, utilizing part of the route of the cancelled Interstate 505, until its interchange with I-405 at the western end of the Fremont Bridge.
US 30 Bypass is the Northeast Portland Highway No. 123. It runs along the following streets before rejoining US 30 in Fairview:
N.W. Bridge Street, N. Philadelphia Avenue, N. Ivanhoe Street, N. Richmond Avenue, N. Lombard Street, N.E. Lombard Street, N.E. Killingsworth Street, N.E. Columbia Boulevard, and N.E. Sandy Boulevard.
U.S. Route 30 Business is a spur from US 30 Bypass northeast of downtown southwest across I-84/US 30 to Oregon Route 99E east of downtown, just east of the Burnside Bridge. It has not rejoined US 30 on its west end since US 30 was moved onto I-405 and I-5 around downtown.
East of Portland
US 30 runs mostly along I-84 in Oregon east of Portland, diverting to short segments of the old surface route to act as a business route or scenic route for I-84:
Note: US 30 uses many different highways (see Oregon highways and routes); the milepoint column shows mileage along these highways, not adjusted for equations, with the highway number in front. The mile column shows the exact distance from the beginning of the road. Not all interchanges on I-84 east of I-205 are shown. For a complete list of interchanges, see the Interstate 84 exit list.