Shoreline began in 1890 with the platting of the neighborhood of Richmond Beach, on Puget Sound, in anticipation of the arrival of the Great Northern Railway the next year. Over the next two decades, Shoreline was connected to Seattle via the Seattle-Everett Interurban streetcar line (1906) and a newly paved North Trunk Road (now Aurora Avenue N., State Route 99) (1913), helping to increase its population.
The name "Shoreline" first came to be applied to this stretch of unincorporated King County in 1944 when it was given to the school district, since the school district boundaries stretched from "Shore to Shore" (Puget Sound to Lake Washington) and "Line to Line" (the old Seattle city limit of 85th St to the Snohomish County Line). Though the modern borders of the city do not stretch to Lake Washington, the area kept the "Shoreline" name.
After the incorporation of Lake Forest Park in 1961, the remainder of the Shoreline School District remained an unincorporated portion of King County. Fifty-one years after it had been named, on August 31, 1995 Shoreline was officially incorporated as a code city and adopted the council-manager form of government. (See City government in the state of Washington.) Residents used Seattle, WA as their address only until 1995 when the city was formed and addresses changed to Shoreline, WA.