Primary State Highway 6 (Washington)

Primary State Highway 6 (PSH 6) was a state highway in the U.S. state of Washington that existed from 1937 until 1970. It ran generally east-west across southwestern Washington, connecting U.S. Route 101 (US 101) near Raymond with US 99 (later Interstate 5, I-5) near Chehalis.

The highway's eastern terminus shifted over time as US 99 was realigned. PSH 6 was superseded by a portion of State Route 6 (SR 6) during the 1970 highway renumbering. The current SR 6 follows a similar but not identical route to the former PSH 6, incorporating some former county roads and local streets into the state highway system. The original designation was meant to connect the coast to inland areas and provide an east-west corridor through the timber-rich regions of southwestern Washington.