This primary source comes from the Records of the Post Office Department.
Full Citation: HI 1917; Post Route Map of the Territory of Hawaii; 1917; Hawaii and Guam; Published State Postal Route Maps, 1894–1957; Records of the Post Office Department, Record Group 28; National Archives at College Park, College Park, MD. [Online Version, https://www.docsteach.org/documents/document/post-route-map-territory-hawaii-1917, May 18, 2024]