Dearborn River High Bridge, Steel road bridge over Dearborn River near Augusta, Montana, US.

The Dearborn River High Bridge is a steel road bridge crossing the Dearborn River near Augusta, consisting of four spans with wooden decking. The structure extends approximately 251 feet (76 m) and rises about 100 feet (30 m) above the water level.

Construction began in 1896 and was completed in 1897 at a cost of $9,997. The crossing had long been a ford used by regional tribes, mainly the Blackfeet, and was known as Ponderay Crossing before the bridge. The river itself was named in 1805 by Lewis and Clark for Secretary of War Henry Dearborn. The Montana Department of Transportation rehabilitated the bridge in 2003, and it was listed on the National Register of Historic Places on December 18, 2003.

Before the bridge, this spot was a ford called Ponderay Crossing, used for years by regional tribes, primarily the Blackfeet; the German source names the Piegan. Lewis and Clark named the river in 1805 for Secretary of War Henry Dearborn. The crossing kept that name until the 1897 bridge replaced the ford.

The bridge is located approximately 15 miles (24 km) southwest of Augusta on Lake Bean Road and remains open to local traffic. Visitors should note that the approach follows rural roads, and daytime visits are advisable for better viewing and navigation.

This is the last remaining pin-connected Pratt half-deck truss in the United States, with decking attached at the center rather than the usual position. This constructional detail makes it a rare engineering survivor worth noting for those familiar with bridge design.