Side A: Pennsylvania & Ohio Canal 1839-1872. The decision to build the P&O Canal resulted from several canal conventions at Warren's first courthouse in 1833. Canal advocates from Warren included Simon Perkins, Leicester King, David Tod, and Calvin Pease. Finished in 1840, this 82 mile canal linked two north-south canals, the Beaver Canal and the Ohio and Erie Canal, via an east-west route for passengers and commerce. By 1856, the Pennsylvania & Ohio Canal was replaced by the railroad and the entire route was abandoned by 1872. (Continued on other side) Side B: The Cross-Cut Canal in Warren. (Continued from other side) On May 23, 1839 a celebration marked the completion of the P&O Canal from Beaver, PA, to Warren. Canal boats crossed the Mahoning River near Van Gorder's Mill. There was a lock on the east side of the Mahoning and a series of locks on the west. The P&O exported coal, iron ore, cheese, butter, and other produce. Sugar, molasses, citrus fruits, and other needed products were imported. The P&O opened previously hard-to-reach markets and brought wealth and prosperity along its entire route, especially the Warren area.