In 1954, Red Bridge is built to span South Fork Stillaguamish River in Snohomish County. The 160-foot-long steel-truss bridge is part of the Mountain Loop Highway and crosses the river between Silverton and Verlot. It is painted red in honor of its predecessor railroad bridge that had rusted to the color red and was thus informally called "Red Bridge."
The bridge is one of the last Pratt/Parker through-truss bridges built in the state. It is a steel riveted bridge. A through-truss bridge is one on which traffic travels between the supporting trusses, at the level of the bottom chords. (On a bridge a chord is a horizontal truss member.) The Pratt/Parker truss is a particular configuration of the individual steel components of the truss.
The bridge was designed by the Bureau of Public Roads office in San Francisco and built by Peter Kiewit Sons Company with steel fabricated by United States Steel located in Gary, Indiana. It forms part of the Mountain Loop Highway, which was built on the right of way of the Everett and Monte Cristo Railway, built in 1892 to haul gold copper, lead, and iron ores to smelters in Everett. The tracks of the railroad were removed in 1932.
The bridge was added to the National Register of Historic Places in 2002 (structure No. 02000311).