4 on the Great Northern Railroad,[5] is a Strauss Heel-trunnion single-leaf bascule bridge spanning Salmon Bay and connecting Magnolia/Interbay to Ballard in Seattle, Washington.

It carries the main line of the BNSF Railway, the Scenic Subdivision, on its way north to Everett and south to King Street Station and Seattle's Industrial District.

The Salmon Bay Bridge, which is located west of the Hiram M. Chittenden Locks, is the last bridge to span the Lake Washington Ship Canal before it becomes Puget Sound.

Built in 1914 by the Great Northern Railway, it has an opening span of 61 meters (200 feet) and has two tracks.

[6][3] In September 2022, the federal government issued a US$25 million dollar grant to fund mechanical upgrades, while BNSF contributed another $70 million dollars toward the effort.