Oregon Slough Railroad Bridge, Railway bridge in Portland, United States.

The Oregon Slough Railroad Bridge is a railway bridge crossing North Portland Harbor with a rotating span design that allows two tracks to pass overhead. The structure connects rail corridors and facilitates freight and passenger train movements through the area.

Built between 1906 and 1908 by the Northern Pacific Railway for the Spokane, Portland and Seattle Railway, the bridge carried its first train on October 23, 1908, and opened for regular use that November. Its swing span was designed by engineer Ralph Modjeski as part of the new Portland–Vancouver line. Ownership passed to Burlington Northern in 1970 and to BNSF in 1996.

The bridge represents early 20th-century industrial development in Portland, demonstrating the influence of rail transportation on regional growth and commerce.

You can see the bridge from viewpoints along the riverbanks where there are straightforward access routes. The best time to visit is during daylight when train movements are clearly visible.

The 8.8 in the bridge's other name, BNSF Railway Bridge 8.8, is its distance in miles from Portland Union Station, the same measure used for Bridge 5.1 over the Willamette and Bridge 9.6 over the Columbia. The swing span opens for river traffic only about 12 times a month, worked by an on-call operator.