State Route 508 (SR 508) is a long

state highway A state highway, state road, or state route (and the equivalent provincial highway, provincial road, or provincial route) is usually a road that is either ''numbered'' or ''maintained'' by a sub-national state or province. A road numbered by a ...

located in Lewis County within the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sover ...

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

, extending from an interchange with (I-5)

concurrent Concurrent means happening at the same time. Concurrency, concurrent, or concurrence may refer to: Law * Concurrence, in jurisprudence, the need to prove both ''actus reus'' and ''mens rea'' * Concurring opinion (also called a "concurrence"), a ...

with (US 12) in

Napavine Napavine is a city in Lewis County, Washington, United States. The population was 1,766 at the 2020 census. History Napavine was officially incorporated as a town on November 21, 1913. Settlers began arriving in the Cowlitz area in the early 1 ...

to in

Morton Morton may refer to: People * Morton (surname) * Morton (given name) Fictional * Morton Koopa, Jr., a character and boss in ''Super Mario Bros. 3'' * A character in the ''Charlie and Lola'' franchise * A character in the 2008 film '' Horton H ...

. By 1916, a road between Napavine and Cinebar was constructed on the current route of SR 508 and was signed in 1937 as (SSH 5K) after being extended to Morton. SSH 5K became SR 508 in 1968 and since then, a segment in Bear Canyon has been reconstructed twice between 2007 and 2009 and a bridge over the

Tilton River The Tilton River is a tributary of the Cowlitz River, in the U.S. state of Washington. Named for territorial surveyor James Tilton, it flows for about , entirely within Lewis County. Course The Tilton River originates in the Cascade Range just ...

was reconstructed in 2009.

Route description

SR 508 begins at a

diamond interchange A diamond interchange is a common type of road junction, used where a controlled-access highway crosses a minor road. Design The freeway itself is grade-separated from the minor road, one crossing the other over a bridge. Approaching the ...

with (I-5)

with (US 12) within

city limits City limits or city boundaries refer to the defined boundary or border of a city. The area within the city limit can be called the city proper. Town limit/boundary and village limit/boundary apply to towns and villages. Similarly, corporate limi ...

. From the interchange, the highway leaves Napavine and travels southeast through an intersection with the Jackson Highway, formerly , to bridge and parallel the South Fork of the

Newaukum River The Newaukum River is a tributary of the Chehalis River in the U.S. state of Washington. It has three main branches, the North Fork, South Fork, and Middle Fork Newaukum Rivers. The length of the three forks and the mainstem river is . The river ...

, passing Onalaska and

Alpha Alpha (uppercase , lowercase ; grc, ἄλφα, ''álpha'', or ell, άλφα, álfa) is the first letter of the Greek alphabet. In the system of Greek numerals, it has a value of one. Alpha is derived from the Phoenician letter aleph , whic ...

before unparalleling the river and continuing east to Cinebar. East of Cinebar, the roadway starts to parallel the

through Bear Canyon to

, where the road becomes Main Avenue and ends at , named Second Street. An estimated daily average of 5,000 motorists used the I-5 / US 12 / SR 508 interchange in 2007, making it the busiest section of the highway; the SR 7 intersection was the busiest section in 1970, with an estimated daily average of 3,200 motorists.

History

A road paralleling the current route of SR 508 first appeared on a map in 1916, extending from

to Cinebar. By 1937, the road was extended east to

and signed as (SSH 5K) in the same year. SSH 5K ran from a branch of (PSH 5) in Morton west to east of Napavine. In 1964, a highway renumbering created SR 508 to replace SSH 5K. Between 1968 and 2008, SR 508 between I-5 and Onalaska used Forest Road and the Jackson Highway to get to Onalaska, but the route was later realigned. In early November 2006, heavy rainfall at Bear Canyon, located east of Cinebar, resulted in erosion of a cliff on the highway that caused portions of the roadway to fall into the

. Construction of the repairs began April 23, 2007 and a limited opening happened on June 25. On July 27, the new road was opened, but during heavy snowfall between December 19 and 22, 2008 and the resulting floods in early January 2009, the area was washed out. On January 29, 2009, SR 508 was reopened through Bear Canyon. A bridge over the Tilton River west of Milton that was built in 1947 and three other bridges on the highway were classified as structurally deficient in 2008 and the Tilton River Bridge was partially closed in April 2009. The bridge, like Bear Canyon, was damaged during floods in January 2009 and reopened on June 11.

Major intersections

References

External links

Highways of Washington StateCompleted WSDOT Projects
{{State highways in Washington related to I-5 508 Transportation in Lewis County, Washington