The Bothell–Everett Highway was built in the 1910s as part of the intercity Pacific Highway and briefly formed part of U.S. Route 99 (US 99) in 1926. The following year, US 99 was moved west to a new highway that would later become modern-day SR 99. The old route to the east was signed by the state as Secondary State Highway 2A (SSH 2A) from 1937 to 1943 and SSH 2J from 1957 to 1964, when it was renumbered as SR 527.