Since the current state highway numbering system was first posted in January 1964, two different highways at different times have been designated SR 121.
Earlier SR 121When first posted as such in 1964, SR 121 started at Jct US 830 at Bingen and headed NW White Salmon, then north via B Z Corner, and Trout Lake to the Gifford Pinchot Nationall Forest boundary near Trout Lake. When US 12 was extended into Washington State in 1967, this SR 121 was renumbered SR 141 .
Before 1964, this route had been SSH 8D
Later SR 121
When the earlier SR 121 was renumbered SR 141, a different highway, SR 801, was renumbered SR 121. This highway started at Jct US 12, formerly SR 8, at Rochester and headed NNE to Littlerock, then east to Jct I-5 at Exit 95 near Maytown. Effective April 1, 1992, SR 121 was changed again. The route west of I-5 was dropped from the state highway system. What had been the end of SR 121, I-5 Exit 95, became the beginning. From I-5, SR 121 now is routed east via Maytown to Tilley Rd S. At Tilley, SR 121 turns left and heads north on Tilley, passing thru Millersylvania State Park. At 93rd Ave SW, SR 121 turns left again, returning to I-5 via 93rd at Exit 99. Today, SR 121 is 7.67 miles long.
Primary State Hwys Secondary State Hwys