Conley Street Bridge

The Conley Street Bridge is a road bridge crossing the Clark Fork River at the western end of Conley Avenue in Deer Lodge. Its design features reinforced concrete beams with vertical sidewalls that run the full length of the span.

The bridge was built between 1907 and 1912 by inmates from the Montana State Penitentiary. It became the first continuous span reinforced concrete T-beam bridge in Montana.

The bridge served as a connection point to Northern Pacific Railway and Milwaukee Road Railroad yards, essential for delivering supplies to the penitentiary.

The bridge carries vehicle traffic across the Clark Fork River and provides a connection point for those traveling through the western area of town. It remains open and accessible to all vehicles using this crossing.

The Historic American Engineering Record documented the structure with survey number MT-161, recognizing its technical importance in American infrastructure history. This designation marks it as a significant example of early reinforced concrete bridge technology.

Location: Deer Lodge

GPS coordinates: 46.39061,-112.73714

Latest update: December 15, 2025 13:22