(Manning to Forest Grove temporarily)
(Forest Grove to Portland temporarily)
(Cannon Beach Jct. to Sunset Camp; Sylvan to Portland; within Portland)
Timber Rd. (Washington County)
(Sunset Camp to Glenwood)
(Glenwood to Gales Creek)
(Gales Creek to Sylvan)
Canyon Road/Jefferson & Columbia Sts.
OR-2 was the route number that was associated with two main highways: the Wolf Creek Highway #47 and the Tualatin Valley Highway #29, but not when the highways were initially assigned. From 1932 to 1939, there was no Wolf Creek Highway (however, the portion between Cannon Beach Jct. and Necanicum Jct. did exist as a part of US-101 until 1939), and from 1936 to 1939 the Tualatin Valley Highway was signed as OR-8 from Forest Grove to Portland (it had previously been signed as OR-47 along the entire highway). But in 1939, work on the Wolf Creek Highway from Cannon Beach Jct. to Portland was underway, creating OR-2 along the entire stretch. Between 1939 and 1942, the road was routed from Cannon Beach Jct. to Sunset Camp along the Wolf Creek Highway and temporarily routed along Timber Rd. (now under Washington County maintenance) and Gales Creek Rd. (now OR-8, but under Washington County maintenance) through Forest Grove, where it picked up the Tualatin Valley Highway to Portland. In 1942, OR-2 was routed off of Timber Rd. and Gales Creek Rd. and onto a new section of the Wolf Creek Highway that was completed to the junction with OR-47 in Manning, making OR-2 multiplex with OR-47 from Manning to Forest Grove; that same year, the Wilson River Highway #37 (OR-6) was completed to Gales Creek from Tillamook, but was temporarily routed along Gales Creek Rd. to Forest Grove, where it was added to OR-2 into Portland. In 1949, the Wolf Creek Highway is completed along its own route to Portland, where it is redesignated the Sunset Highway #47; OR-2 is moved to this routing, leaving OR-6 (later OR-8 again) along the Tualatin Valley Highway. However, OR-2's days were short-lived, as when US-26 was extended into Oregon from Grand Teton National Park all the way to Astoria, the route it replaced from Portland to Cannon Beach Jct., was OR-2.
As far as I can tell, all three of these routings ended at US-99W in Portland, which at the time was routed onto 4th and 6th Aves and was moved onto Harbor Drive in 1950. With this move, OR-2's eastern terminus was extended 5 more blocks to meet US-99W at Harbor Dr. Some maps continued to show both OR-2 and OR-6 long after US-26 replaced them through Portland in 1952. I'll put up map scans soon.
Interestingly enough, on a 1941 Shell Map (shown on the right), the portion of OR-2 between Forest Grove and Portland appears to be a multiplex of OR-2 and OR-8, even though OR-8 had been decommissioned for 2 years. Both the construction of OR-6 and a proposed Sunset Highway (a future alignment of OR-2 and current US-26) can also be seen. Finally, the portion from Cannon Beach Jct. and Necanicum Jct. was still shown as a part US-101, even though the new US-101 had been built for 2 years.
On a somewhat related note, some maps, mainly Thomas Guides, seem to think that there's still an OR-2, and even an OR-2W. OR-2 appears to be cosigned with I-84/US-30 through the Columbia Gorge, and OR-2W appears to be cosigned with US-30 through Columbia County. They are not; however, I-84/US-30 through the Gorge is known as Oregon State Highway #2, and US-30 from Portland to Astoria is known as Oregon State Highway #2W. The Thomas Bros. must not know the difference between Oregon's posted routes and its hidden highway numbers (though I'll admit, sometimes I don't either).
There are three alignments shown in the map above, and all are still intact. There's the 1939 alignment, which is routed from Sunset Camp through Glenwood on Timber Rd., Glenwood to Gales Creek along what is now OR-6, and Gales Creek to Sylvan along what is now OR-8 (locally known as Gales Creek Rd., Pacific Ave., 19th Ave., Baseline St., the Tualatin Valley Highway, and Canyon Rd. in its various incarnations). Then there's the 1942 alignment, which was routed from Sunset Camp to Manning along what is now US-26, Manning to Forest Grove along what is now OR-47, within Forest Grove most likely along Sunset Dr., and from Forest Grove to Sunset along OR-8. Finally, there's the 1949 alignment, which is routed completely along what is now US-26 from Sunset Camp to Sylvan. Also, old OR-2 segments enter Portland along Canyon Rd.; simply take US-26 East and take Exit 73 to head to Canyon Rd., which turns into Columbia St. Follow to Front Ave. From Portland, take Jefferson St. all the way until to merge onto US-26 Westbound. Also, the segment of old OR-2 from Cannon Beach Jct. to Sunset Camp is routed along what is now US-26 and hasn't changed since 1939 at the inception of the highway.