McCammon developed in close association with transportation. In early 1863, William Murphy built the first toll bridge, and McCammon became the nucleus of the Overland Stage Lines. After Murphy's death, H.O. Harkness acquired the toll bridge. In 1881, Utah Northern Railroad purchased the right-of-way and named the rail station for U.S. Assistant Attorney General J.K. McCammon, who had negotiated a peace agreement with the Shoshone and Bannock Tribes in 1867. That same year, Union Pacific Railroad constructed a line from McCammon northward to the mining country of Montana. Postal service began in 1883. The first frame building, erected in 1885, had two rooms and a platform on three sides, and John J. Stewing served as the first telegraph operator and station agent. The depot became a focal point for the business and social life of the growing community, where immigrant pioneers found work in freighting, farming, and ranching. In 1892, McCammon became a railroad junction linking the Oregon Short Line and Utah Northern Railroads, and as "Junction City" it became the chief dispatch center. As business increased, a larger station was built by John Hood, Harry Skinner, Henry and Albert Lish, Albert Henson, Joel Lewis, John Hallen, George Gittins Sr. and Jr., and Edwin and Eddie Gittins. The new depot was divided into thirds, with a passenger waiting room heated by a round coal stove, a central office with the telegraph and ticket window, and a north end for mail bags, express packages, and a large safe for money, while the south end served as a freight room for large and heavy goods kept under lock and key. Local hotels and businesses accommodated travelers, and U.S. mail was received and dispatched three times daily. A modern depot was erected in 1900 with larger rooms and customer amenities, and the building now serves as McCammon's City Hall, while the old depot was moved west of the tracks and used as a freight house.