In 1923, the Indian Timothy Memorial Bridge is built in Asotin County on U.S. 12, spanning Alpowa Creek, not far from the Snake River. It is a concrete-arch bridge build in a "rainbow arch" design made popular in the 1910s and 1920s by James Marsh, an engineer from Des Moines, Iowa.
The two-span, reinforced-concrete bridge was dedicated to Ta-Moot-Tsoo (Chief Timothy [1808-1891]). Chief Timothy was a Nez Perce Indian who was friendly with early settlers and was credited with saving the lives of Colonel Edward J. Steptoe's troops in 1858 after their defeat in the Battle of Tohotonimme, near Rosalia.
The bridge was erected by the Colonial Building Co. of Spokane on what was then known as the old Inland Empire Highway (later SR 12, later still, U.S. 12) that connected Clarkston with Walla Walla and the Tri-Cities. The bridge has 20-foot-high ribbed arches, and is known as a half-through structure because it is braced only below the deck and lacks overhead cross-bracing ties (a through structure is braced above and below traffic). Engineers gave the balustrade-style guardrail arched openings, and made the concrete arches smooth to mirror the area's high, rolling prairie hills. According to Craig Holstine and Richard Hobb in their Spanning Washington, these design effects may have had Chief Timothy's approval.
In 1982, the bridge was listed on the National Register of Historic Places (Structure -- No. 82004194). It is no longer in use, but is a roadside attraction at a highway pullout.