United States. Post Office Dept. "Post route map of the states of Montana, Idaho and Wyoming showing post offices with the intermediate distances and mail routes in operation on the 1st of December, 1903." Map. Washington, D.C.: Post Office Dept., 1903. Norman B. Leventhal Map & Education Center, https://collections.leventhalmap.org/search/commonwealth:cj82km95s (accessed June 28, 2022).