State Route 403 (SR 403, now known as the Altoona–Pillar Rock Road[1]) was a state highway in Wahkiakum County, in the U.S. state of Washington. It extended 10.4 miles (16.7 km) from Pillar Rock northwest to SR 4 in Rosburg. The route served as a connector to Pillar Rock. The highway was Secondary State Highway 12C (SSH 12C) from 1943 until 1964, which ran from Pillar Rock to Rosburg. In 1991, SR 403 was removed from the state highway system.
Route description
SR 403 ran 10.4 miles (16.7 km) from Pillar Rock northwest to SR 4 in Rosburg. The route served as a connector to Pillar Rock.[1][5] The road started at Pillar Rock, a natural rock formation along the Columbia River. SR 403 went west and passed the communities of Brookefield and Altoona while paralleling the Columbia River's shoreline. The highway then went northwest and then curved westward before reverting to a more northern route to Rosburg. In Rosburg, SR 403 ended at an intersection with SR 4.[1][6]
^Washington State Legislature (1937). "Chapter 207". Session Laws of the State of Washington (1937 ed.). Olympia, Washington: Washington State Legislature. Retrieved November 29, 2008.