Railroads and roads in the Sammamish River and Snoqualmie River valleys, where modern-day SR 202 runs, were built during the late 19th and early 20th centuries. The early roads were incorporated into the Yellowstone Trail in the 1910s and became a state highway in 1925. SR 202 was established in 1964 as part of a new state highway system, running from Woodinville to Monroe; SR 522 was designated to the Woodinville–North Bend highway, continuing west to Seattle. By 1970, the designations were reversed, with SR 202 moved to the Woodinville–North Bend highway, and SR 522 moved to the Bothell–Monroe highway.