Beginning with William H. Murphy’s toll bridge on the Portneuf River in 1865, used mainly by miners traveling from Utah to the Montana goldfields, McCammon’s early growth became closely tied to Henry O. Harkness. Murphy and his wife Catherine Scott Murphy hired Harkness to help with business operations; after Murphy died in 1869, Harkness married Catherine in 1871, and after Catherine’s death in 1898 he married her niece, Sarah Scott, with whom he had five children. As railroads reached McCammon by 1882, including the Oregon Shoreline and Utah and Northern Railroads, Harkness expanded into ranching, lumber, milling, horses, sheep, cattle, and general merchandise. The Harkness Ranch grew to include a flour mill on the Portneuf River in 1891, and Harkness later built a new hotel in 1903 to attract railroad travelers and a 600-seat opera house in 1905 with a slanted floor that could be leveled in 10 minutes for dancing, where masquerade balls were popular. McCammon’s strategic location was reinforced by its role as a railroad hub; by 1908 it was incorporated, and by 1910 its population was estimated at 800 to 1,000 residents. Harkness died in 1911 at age 77, the hotel burned in 1913, and only remnants of his empire remain.