The Polebridge to Numa Ridge Phoneline is a historic communications path in Glacier National Park in the U.S. state of

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...

. The line was the last remaining single-line crank telephone network in the American West. The remaining line, insulators, and terminals are instructive of early communication technology. The system includes the remains of a single strand system using an

earth ground In electrical engineering, ground or earth is a reference point in an electrical circuit from which voltages are measured, a common return path for electric current, or a direct physical connection to the Earth. Electrical circuits may be con ...

. Wire was strung through ceramic insulators mounted on trees. Phone poles still stand in the meadow south of Kishenehn Ranger Station, and a phone remains in place at Bowman Lake. The line starts at Polebridge Ranger Station, passing

Skyland Camp-Bowman Lake Ranger Station The Skyland Camp-Bowman Lake Ranger Station in Glacier National Park was originally built as the Culver Boys' Military Academy. The main building, known variously as the Skyland Camp Messhall, Culver Boys' Military Academy Messhall and Skyline Ch ...

, then

Numa Ridge Fire Lookout The Numa Ridge Fire Lookout in Glacier National Park is significant as one of a chain of staffed fire lookout posts within the park. The low two-story timber-construction structure with a pyramidal roof was built in 1933. The lookout was built t ...

. The first sections were constructed in 1911, with additions to connect ranger stations through the 1930s. In later years, FM radio saw greater use and the extent of the phone system declined. The Polebridge-Numa line persisted until 1985, when it was officially shut down, although unofficial use continued through 1988.

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{{National Register of Historic Places Park buildings and structures on the National Register of Historic Places in Montana History of telecommunications in the United States Telecommunications infrastructure on the National Register of Historic Places National Register of Historic Places in Flathead County, Montana 1927 establishments in Montana National Register of Historic Places in Glacier National Park Infrastructure completed in 1927 1927 in technology