The next historic bridge listed by MDOT along M-28 is over the Sand River in Onota Township in Alger County. While not visible to motorists, the bridge, constructed in 1939, is the longest rural rigid-frame span in Michigan. Most bridges of this type were built in urban locations, and soil conditions in the state limit locations for this style of bridge. The bridge over the East Branch of the Tahquamenon River in Chippewa County was built in 1926 as a "formative exercise in what would evolve into a state standard design." The bridge was built with nine lines of I-beams encased in concrete. Only one other bridge in Michigan was built with such concrete encasement.