The current route of the highway was first established in 1967 as Secondary State Highway 11I (SSH 11I) and became SR 170 in 1970 after it was moved north of its previous route, which had been on maps since 1926, named SSH 11A in 1937 and renumbered to SR 170 in 1964.

The old route ran from the Columbia River southwest of Basin City to SR 17 north of Mesa.

Once the roadway enters Warden, it is named 1st Street and later ends at Main Avenue.

[4][5] The busiest segment of the road in terms of vehicle counts was between SR 17 and Warden, with a daily average of 2,800 motorists in 2007;[6] the busiest segment in 1970 was at Main Avenue, with a daily average of 2,100 motorists.

[9] By 1981, BNSF Railway owned both crossings and as of 2009, the Columbia Basin Railroad operates both.