Susitna River Bridge, Railway truss bridge in Matanuska-Susitna Borough, United States.

The Susitna River Bridge, also called the Gold Creek Bridge, carries the Alaska Railroad across the Susitna on a 504-foot steel through-truss main span completed in February 1921. Flanking it are two 121-foot combination Howe truss spans and two 70-foot pony Howe truss end spans, with 392 feet of trestle on the southern approach and 28 feet on the northern, for a total length of 1,322 feet.

The American Bridge Company built this crossing between 1920 and 1921 as part of the government railway expansion in Alaska. The project created a crucial link in the railroad network that was being developed across the territory.

The bridge was added to the National Register of Historic Places in 1977 because it represents how railway connections shaped transportation development in Alaska. Today visitors can see how the steel structure reflects the role of engineering in opening up remote regions.

The structure sits about 150 miles north of Anchorage and remains in active use by the Alaska Railroad Corporation for train transport. Visitors should be aware that the bridge primarily serves rail operations and viewing requires caution and awareness of train movements.

The concrete for the main piers used aggregate from a glacial moraine in front of Spencer Glacier, 56 miles north of Seward, because local pits contained humus; 7 percent sand was added to the bank aggregate. A partial pier failure in September 1920, blamed on poor cement, humus and cold air and water, led to special placing measures.