In December 1965, the U.S. Postal Service awarded a contract for a new post office to be constructed in the Sioux County community of Ireton. The 1,584-square-feet building, which featured a loading dock along and dedicated parking space, was officially dedicated October 1966. The dedication ceremony included a speech from U.S. Congressman Stanley L. Greigg, an Ireton native. He said the new building was “like a shiny penny on main street.” Around 100 residents attended the ceremony.