Mill Rock Bridge, Spanning Big Bear Creek, Monmouth, Jackson County, IA

Significance: The Mill Rock Bridge was erected by Clinton Bridge & Iron Works, a major Iowa bridge contractor. It is locally significant as an early instance of the use of riveted connections and concrete deck in county bridge construction. These were among features which were to become standard in subsequent decades due to the establishment of the Iowa State Highway Commission and the Commission's enforcement of design standards for various kinds of crossings. Because the Mill Rock Bridge does not display all features associated with this standardization program, it may be considered an illustration of the transition from county to state control of local bridge design and construction.
Survey number: HAER IA-7
Building/structure dates: 1913 Initial Construction