Analysis of information sources in references of the Wikipedia article "Washington State Route 523" in English language version.
(j) Secondary State Highway No. 1J; beginning at a junction with Primary State Highway No. 1 in the vicinity north of Seattle, thence in an easterly direction by the most feasible route to the vicinity of Lake Washington, thence in a southeasterly direction by the most feasible route to Seattle in the vicinity of the Naval Air Station at Sandpoint.