 The corridor of US 2 was signed as US 10 from Peshastin to Spokane and US 195 from Spokane to Newport, co-signed with State Road 2 and State Road 6, respectively.The Washington primary and secondary state highway system was adopted by the Washington State Legislature on March 17, 1937, and the three highways that comprise the present route of US 2 were included in the system as Primary State Highway 15 (PSH 15) from Everett to Peshastin, PSH 2 from Peshastin to Spokane, and PSH 6 from Spokane to the Idaho state line in Newport via a short branch route.US 10 was relocated to a southern route in 1939, crossing the Columbia River at Vantage, and the former route was replaced by US 10 Alternate the following year.