Washington State Route 401

State Route 401 (SR 401) is a long state highway in Pacific County within the U.S. state of Washington. The highway originates at the north end of the Astoria–Megler Bridge west of Megler at an intersection with (US 101). The roadway travels northeast, paralleling cliffs, the Columbia River and the South Fork of the Naselle River to Naselle, ending at . The road was designated Secondary State Highway 12B (SSH 12) between 1937 and 1964, when SR 401 was created to replace SSH 12B. The Astoria–Megler Bridge, completed in 1966, replaced a ferry east of the bridge, where the highway originally ended, and is known locally as Kingston Ferry Road. The roadway was extended west to the north end of the bridge, where it currently terminates. The former ferry terminal became the Dismal Nitch rest area, named after the Lewis and Clark Expedition's description of the place.