Located a short distance south of Mankato in Blue Earth County, Kern Bridge once carried County Road 190 over the Le Sueur River near the community of Skyline. Engineered as bowstring through truss, the Kern Bridge is a rarity in Minnesota, most likely because that bridge type was falling from favor in the last of decades of the nineteenth century. Erected in 1873 by the Wrought Iron Bridge Company of Canton, Ohio, Kern Bridge is one of the state’s oldest crossings. In fact, it is the oldest truss bridge of any kind in Minnesota.
Named for John Kern, a local farmer whose property abutted the bridge site, the structure measures 189 feet long. It is held together with pins, which are located at each bridge joint. The bridge’s bowstring arch through truss design was patented by Squire Whipple in 1841. A graduate of Union College in New York, Whipple was a renaissance personality—serving as a schoolteacher, farmer, surveyor, and bridge engineer. Whipple may have been the nation’s most famous designer of bridge trusses of that era. Ultimately, his later invention of the double-intersection truss (or Whipple truss) proved even more popular than the bowstring.
Now more than 140 years old, Kern Bridge rests unassumingly on its historic site, surveying the Le Sueur River. It no longer accommodates traffic and its long-term fate is unknown. On this quiet township road, access to the bridge is limited, hindered in part by boulders near the approaches. To a large degree the bridge is masked by dense foliage, making it difficult to see from the roadway, although it is a familiar sight to those that paddle the Le Sueur River. It is likely that the residents of Blue Earth County will work to save this rare bridge, given their success in preserving and rehabilitating the Dodd Ford Bridge (1901) near Amboy. Blue Earth County is home to a variety of bridges, from some of the state’s earliest reinforced-concrete bridges, as well as numerous metal truss bridges.
Gardner, Denis P. Wood, Concrete, Stone, and Steel: Minnesota’s Historic Bridges. Minneapolis: University of Minnesota Press, 2008.
Gimmestad, Dennis, “Kern Bridge,” Blue Earth County, Minnesota. National Historic Landmark Places Inventory-Nomination Form, 1980. U.S. Department of the Interior, Washinton, D.C.