(within Astoria; Hwy #102 MP 0.00-1.42, 1.42 miles)
"Over the Nehalem Highway from its junction with the Oregon Coast Highway, US101, in Astoria (common with US101 Business in Astoria), southeasterly via Jewell to its junction with the Mist-Clatskanie Highway, OR47, at Mist. (Rev. 5/25/2005)"
~ ODOT, Descriptions of US and Oregon Routes, March 2007
OR-202 was created at the inception of Oregon's secondary route numbering system in 1935, running between Astoria and Mist in northwest Oregon. I have this theory that, for one year, OR-202 actually ran all the way down to Forest Grove, meeting OR-47 (Tualatin Valley Highway #29); this is because OR-47 was extended north all the way to Clatskanie in 1936, and I don't think that Oregon would end OR-202 at a county road while its associated state highway continued southward. Since I have no maps from that long ago to back it up, it's just conjecture at this point. If you have a map from 1935 that shows this, please e-mail me and let me know.
What clearly is not conjecture is that in 1965, when a new routing of US-101 across Youngs Bay, US-101 Business was created over the old route, and OR-202 was extended along its northern portion. A milepost resynchronization was added sometime between 1980 and 2000, shortening the highway by 0.11 miles to its current length. I have found no grand cause for this, my guess is that measuring technology became better and ODOT didn't want to replace all of the mileposts along the route.
Google Earth (while good for finding old alignments from the air but not good for accurate road numberings) mislabels a portion of OR-47 between Mist and the Columbia-Washington County Line as being cosigned with OR-202.