Glacier National Park, on the US side, and Waterton National Park, on the Canadian side, are two national parks which, together, form a World Heritage Site, a UNESCO Biosphere Reserve and an International Peace Park, the world's first! Stretching through Glacier National Park, from its western edge to its eastern edge, is a road named Going-to-the-Sun Road. The Road, nearly 50 miles in length, took 11 years to be completed. With construction beginning in 1921, it was not until 1932 that the first car journeyed the complete route from the west gate of Glacier National Park to the east gate at St. Mary. It wasn't until the following year that, with both U.S. and Canadian dignitaries on hand, Going-to-the-Sun Road was officially opened on July 15, 1933. It was this road which finally allowed access from either of its ends to the interior of one of the most scenic National Parks in the country.
About 390 metres (1,300 ft) northwest of the St. Mary Visitor Centre and the east park gates the road crosses over the St. Mary River, carried by this triple arch bridge. Here emptying Upper St. Mary Lake into Lower St. Mary Lake, its waters ultimately reach Hudson's Bay in Canada, and the Atlantic Ocean.
Built the year following the official opening of Going-to-the-Sun Road, the triple arches of the bridge continues to carry nearly a half million vehicles per year into the park. Since its construction the bridge has withstood more than one major flood, testifying to the adroitness of its designers and builders, and to the stoutness of its construction.
Following is a description of the bridge as described in Glacier National Park's NRHP Nomination Form.
St. Mary River Bridge
The two-lane asphalt paved road crosses a number of creeks over stone faced bridges, passes through two tunnels and between a series of stone retaining walls. These are contributing features to Going-to-the-Sun Road.
Built in 1934, the three-span continuous concrete slab bridge is rock faced. The railings are rubble stone masonry. The bridge is 140' in length, 26' in width with 4' shoulders. The bridge is in good condition, but the railings do not meet current AASHTO standards.
Photographs of all of the contributing structures, i.e. bridges, will be photographed during the summer of 1983 and will be sent to the National Register of Historic Places as additional documentation.
From the NRHP Nomination Form, Item Number 7, Page 2