When the current state highway numbering system was first posted in January 1964, SR began at Jct SR 900 on the west side of Issaquah and headed northerly along West Lake Sammamish Parkway to Redmond. A spur headed east from Lake Sammamish Parkway to connect with SR 522 (renumbered SR 202 in 1970) in Downtown Redmond. The mainline headed west from West Lake Sammamish Parkway to Downtown Kirkland then south via Lake Washington Blvd to Jct SR 520.
In 1971, the predominately east-west portion of SR 901 from Redmond to Kirkland and the Kirkland south to SR 520 portion were renumbered SR 908. That same year the south end of SR 901 was shifted from Jct SR 900 in Issaquah to I-90 Exit 13.
Effective April 1, 1992, West Lake Sammamish Parkway was dropped from the state highway system and SR 901 was shifted to N Front St and East Lake Sammamish Parkway from I-90 Exit 17 in Issaquah to Jct SR 202 on the east side of Redmond. Residents east of Lake Sammamish complained about the designation of East Lake Sammamish Pkwy as a state highway. The 1992 legislature passes a law dropping East Lake Sammamish Parkway from the state highway system effective in June 1992. Technically East Lake Sammamish Parkway was a state highway for about 10 weeks but no SR 901 signs were posted along it.
Before 1964, SR 901 had been SSH 2D
Primary State Hwys Secondary State Hwys