On 29 March 1912 the Tremonton Commercial Club was organized with Aquilla N. Fishburn as president, Charles McClure as vice-president, Harry L. Gephart secretary, and S.N. Cole treasurer. The club voted to organize a hotel commission. David Holmgren was chairman of the commission, which at once began the erection of the Midland Hotel. The contractors soon learned that the underground water was too near the surface to make the building of foundations and basements either safe or possible. Therefore, Matthew Baer organized a drainage company in July 1913, and by November of that year a sewer and drainage system had been extended to the greater portion of the town.

From the summer of 1912 to the close of 1914 Tremonton experienced a building boom. Coles Bank, the Shield Hotel block, Waldron and Harris Mercantile Building, and the Midland Hotel were all built. On 6 May 1918 Tremonton was incorporated as a city of the third class with Charles McClure as mayor; J.A. King, David Holmgren, W.H. Stone, and H.T. Woodward, city councilmen; Louis Brenkman, clerk; and W.E. Getz, treasurer. That same year, the city voted a $50,000 bond and installed a new water system using water from the Johnson Spring located just east of Point Lookout. By 1925 the population of Tremonton numbered 1,000.