SR 31 starts at Jct SR 20 at Tiger and heads north via Ione, Metaline, and Metaline Falls to the Canadian Border. BC 6 connects with SR 31 at the border. When first posted as such in 1964, SR 31 started at Jct US 2 in Newport. The Newport to Tiger portion of SR 31 became part of SR 20 in 1973 when SR 20 was extended east to Newport after the completion of the North Cascades Highway in September 1972. Today, SR 31 is 26.79 miles long.
Before 1964, SR 31 was part of PSH 6.
Primary State Hwys Secondary State Hwys