In 1854, the new Mosinee post office building moved from the east side of the Wisconsin River to the west side. The first settlers had settled on the eastern side, along the major road that connected Mosinee to the wider world. But the geography of the area limited expansion along the eastern riverbank. By the late 1850s, the growing community would largely build new homes and businesses on the other side of Little Bull Island. This also meant that even more than other communities along the Wisconsin River Valley, Mosinee would need a good bridge to cross at the Little Bull Falls. The lumberjacks had long known the swift rapids and rocky sections of Little Bull Falls made it the most dangerous place on the whole Wisconsin River. Mosinee’s first real bridges were wooden, held together with a few iron bolts. They were built with latticework-style walls and open at the top. The wooden bridges crossed in sections; first to the island over the eastern “jaws of the gorge,” then over to the western side further down the island. Over the years, new bridges crossing the gorge were built to replace the old covered bridge. By the turn of the century, steel truss bridges had replaced the old wooden ones. In the 1930s, Mosinee got a new “super bridge” made of concrete and steel. The building of the paper factory on the site of the old sawmill led the Village of Mosinee to quickly develop and expand in the first half of the 20th century. With the greater importance of automobiles and the highways, it became clear that a modern bridge was needed to handle the larger volume of traffic passing through town. The current bridge arrangement, bringing traffic directly across the Wisconsin River, came with a modern bridge built in 1963