In 1909, The Leinart Company, composed of T.H. Leinart, J.O. Leinart, and R.E. Leinart, purchased this property. A smaller wooden post office building had stood here before the big 1908 Market Street fire, but it was soon replaced in 1909 by this iconic structure with arches of colored brick and brownstone trimmings. After construction, the post office occupied the first floor, with offices on the top two floors. When the Clinton Library Association was organized in 1912, its reading room occupied the third floor.