Dearborn River High Bridge

Dearborn River High Bridge
File:Dearborn River High Bridge kleiner.jpg Dearborn River High Bridge in May 1980
Crosses	Dearborn River
Locale	Lewis and Clark County, Montana
Maintained by	County Highway Agency
ID number	L25300009+00001
Characteristics
Design	Pratt half-deck truss
Material	Steel, concrete, stone
Total length	251 feet (77 m)
Width	16.1 feet (4.9 m)
Height	100 feet (30 m)
Longest span	160.1 feet (48.8 m)
History
Designer	Zenas King of King Bridge Company, Cleveland, Ohio
Construction end	1897
Statistics
Daily traffic	100
Dearborn River High Bridge
U.S. National Register of Historic Places
Location	About 15 miles southwest of Augusta, Montana on Bean Lake Road
Coordinates
Area	9 acres (3.6 ha)
Built	1897, rehab 2003
Architect	King Bridge Company
Architectural style	Pratt half-deck truss
NRHP reference No.	03001298
Added to NRHP	December 18, 2003
Location

The Dearborn River High Bridge is a Pratt half-deck truss bridge built in 1897, and has been placed on the National Register of Historic Places as it is one of the few bridges of its type left standing in the United States. On a half-deck bridge, the deck is attached in the center rather than, as is more common, top or bottom of the superstructure. It crosses the Dearborn River on Lake Bean Road (Montana Secondary 435) about 15 miles (24 km) southwest of Augusta, Montana. The unusual design of the Dearborn River High Bridge suits it to carry light loads across high/deep crossings. It has four spans and a wooden plank deck. It is the last standing pin-connected Pratt half-deck truss bridge left in the United States. Construction cost was $9,997. Construction began in 1896 and completed in 1897.

This crossing point on the Dearborn River had been used for many years by the local Indian tribes, primarily the Blackfeet. Prior to the bridge's construction this location was known as the Ponderay Crossing. The river was named for United States Secretary of War Henry Dearborn by Lewis and Clark in 1805. The area was left largely unexplored by Europeans for the next 50 years or so. The bridge was rehabilitated in 2003 by the Montana Department of Transportation, with Sletten Construction of Great Falls, Montana as the lead contractor, and was placed on the National Register of Historic Places on December 18, 2003.

See also

• List of bridges documented by the Historic American Engineering Record in Montana
• National Register of Historic Places listings in Lewis and Clark County, Montana

External links

• Historic American Engineering Record (HAER) No. MT-23, "Dearborn River High Bridge, Spanning Dearborn River, Augusta, Lewis and Clark County, MT", 11 photos, 4 color transparencies, 4 data pages, 3 photo caption pages
• Dearborn River High Bridge at Structurae
• Dearborn River High Bridge / Lewis and Clark County, Montana bridgehunter.com
• Dearborn River High Bridge in Central Montana bigskyfishing.com