W.A. Irwin, a developer from Santa Monica, California, who owned thousands of acres and established colony tracts, laid out Irwin City, surveyed by George Manuel and recorded on May 8, 1907. The colony stood less than a mile south of present-day Hilmar, and Irwin promoted it in brochures as having the best climate in the world, with no hard winters, snow storms, or cyclones, only eternal summer. Irwin City had a hotel, bakery, jeweler, barber, Hedman-Johnson Meat Market, Johnston Hardware, Ceylon Grocery, and a general merchandise store run by A.H. Boothry and sons. The building now known as Irwin City antiques was previously Pedigo's Store and later Klint's Hardware. Nearby stood a two story building called Fallen Angel Saloon, with a hotel on the upper floor. In 1911 a U.S. Post Office opened in Thomas Pedigo's General Store and operated until 1958; Pedigo was postmaster and later became a circuit judge for the area. In 1917 the Tidewater Southern Railroad line reached the area and laid out the town of Hilmar just to the north. As Hilmar grew southward, Irwin City began to be absorbed, yet it did not disappear, and businesses and organizations still use the name Hilmar-Irwin. Train service halted in 1954, trucks took over transporting farm produce, and what had once been two competing towns became one.