designated in 1913. During a 1923 renumbering of the state road system, State Road 19 became State Road 12, which ran from Megler north to Raymond and east to Chehalis. Primary State Highway 12 (PSH 12) replaced State Road 12 when the Primary state highways were created in 1937; PSH 12 didn't begin in Megler, but began in Kelso. Between Raymond and Chehalis, PSH 12 was paralleled by numerous railroads that have changed over time. In 1951, the Northern Pacific Railway followed the route from Raymond to Chehalis, but by 1958, the Pe Ell Prairie Railroad replaced Northern Pacific from Pe Ell to Dryad and the Chehalis Western Railroad, now the Chehalis Western Trail, replaced Northern Pacific between Adna and Chehalis. In 1968, the Chehalis Western Railroad no longer operated in the Adna area and the last railroad to parallel current SR 6 was the Puget Sound and Pacific Railroad, which runs from Adna to Chehalis. During the 1964 highway renumbering, PSH 12 was split into US 830, US 101 and SR 6. The only other highway to intersect SR 6 was SR 603, the only auxiliary route of the highway, which was established in 1964 and decommissioned in 1991. Following a major winter storm in December 2007, an section of SR 6 near Pe Ell was closed due to landslides and an unstable slope above the highway. The roadway was reopened for limited access by the end of the month while work began on clearing debris on the unstable slope. The section fully reopened to traffic on March 16, 2008. During the stabilization of the slope near Pe Ell, similar work started in February on another slope located near Frances that was finished in late April. The highway's bridge over the South Fork of the Chehalis River west of Chehalis was originally built in 1925 and was replaced by the state government in 2009. The new bridge, measuring wide, was constructed to the north of the existing structure and was opened to traffic in September 2009. The project was the first of four bridge replacements on SR 6 that were funded by the 2005 transportation package. Construction of a $3.3 million pedestrian bridge over the highway was begun in 2021. Located west of Claquato, the bridge would lessen vehicular dangers for users of the Willapa Hills Trail, which meanders alongside the road from Chehalis to South Bend. Major intersections