 Primary Road 44 extended from Primary Road 10, now Iowa Highway 3 to Rolfe, while Primary Road 43 extended from Armstrong to the Minnesota state line.By 1947, Iowa Highway 44 had been created along the same route Iowa 15 now occupies.In 1969, then-Iowa Highway 44 was redesignated as Iowa Highway 15 to match Minnesota State Highway 15 at the state line.