Records of the Bridge Engineer which include lists of river traffic on the main channel Mississippi River wagon bridge at La Crosse, Wis., from 1901 to the bridge’s closing in Sept. 1939. Information generally included the name of and the date and time a vessel passed through the opening of the swinging span. Occasionally an engineer would note what the vessel was carrying, such as logs or lumber. Generally steamboats and barges required use of the swinging span. The original order of these volumes has been maintained.

One of the best uses of this series is identifying the volume of river traffic that required the bridge to be opened. The height of traffic was between 1895-1916, just at the tail end of the lumber trade in La Crosse.