Steptoe is a small unincorporated rural town in Whitman County, Washington, United States. The ZIP Code for Steptoe is 99111.A post office called Steptoe was established in 1875. The community is named after Colonel Edward Steptoe for a battle located north of Steptoe near Rosalia, Washington. U.S. Route 195 runs through Steptoe, connecting it with the county seat, Colfax, 11 miles to the south and the region's largest city, Spokane, 43 miles to the north.