 Mrs. Maggie Classen owned several lots in Hallam, unusual for a woman in the 1890s, upon which were built the telephone office and a doctor's office.By the early 1900s, Hallam featured a bank, a hardware store, a dry goods store, a shoe shop, a druggist, a livery barn, and a doctor.In 1962, the second nuclear power plant in the United States was completed in Hallam.