Historical Marker
The Natural Pier Bridge
Alberton, Mineral County · Montana
The rock was holding up a bridge before this one. Missoula County had already set a timber through truss on the same outcrop, and Mineral County, split from Missoula County only two years before, replaced it as part of a plan to carry the Yellowstone Trail to the south bank. Its twin at St. Regis, built by Wausau Iron Works, does not survive intact. This bridge kept the highway for little more than a decade: in 1932 new state deck trusses near Tarkio and at Cyr took it away. The Montana Department of Transportation rehabilitated the bridge in 1999.
What the plaque says
The Natural Pier Bridge This structure is an example of how engineers incorporated a natural feature into the design of a bridge. Designed by Montana Highway Department bridge engineers, the bridge is a standard riveted Warren through truss. The bridge is unusual in that one of the piers is anchored to a rocky outcrop in the Clark Fork River. The bridge was once part of the Yellowstone Trail- which traversed Montana from Lookout Pass to the South Dakota border in southeastern Montana. Responding to pressure from the lumber companies and the Yellowstone Trail Association, Mineral County embarked on an ambitious bridge-building program in 1916. Although the county was responsible for the construction of the bridge, fiscal limitations and its location near the Lolo National Forest forced the county commissioners to seek financial aid from the federal government. In early 1917, the county contracted with the Missoula-based Lord Construction Company to build the bridge. Work progressed steadily on it for several months when the county ran out of money for its construction. After securing additional federal funds, the county commissioners called a referendum to raise money to complete construction of the bridge. Because of the law, however, the vote could not be held for several months. With the money eventually acquired, the bridge was completed in 1918 at a cost of $100,000.
Where it stands
47.01448, -114.50669 · Directions
Worth the stop nearby
- Ninemile Remount Depot — 6.2 miThe Forest Service's mule ranch, built because the fires of 1929 ran out of packers.
- Missoula Smokejumper Visitor Center — 21 miThe base of the crews descended from the first two men ever to parachute onto a forest fire.
- Fort Missoula — 24 miAn 1877 Army post that held Italian seamen and Japanese immigrant men behind its fence in World War II.
- Fort Fizzle — 24 miA log barricade built to stop the Nimiipuu in 1877. They climbed the ridge behind it and walked around.