According to the Site-Seeing in Old Westport written by the Westport Historical Society, traffic had become so heavy within the area of the library's location. Due to the traffic, a horsecar rail line was installed between Kansas City and Westport. In order to afford the line, a tax was levied on the citizens of Westport.
With the money left over after the line was put in, the Allen Library was built. The library is named after Judge Arthur M. Allen. Judge Allen had been a large force in the construction of the horsecar rail line.