The Ballard Bridge, also known as the 15th Avenue Bridge, is a double-leaf bascule bridge in Seattle, Washington. It carries 15th Avenue NW over Seattle's Salmon Bay between Ballard to the north and Interbay to the south. The Ballard Bridge follows the Fremont Bridge in the east in the succession of bridges spanning the Lake Washington Ship Canal, which connects Lake Washington in the east to Puget Sound in the west.

The Lake Washington Ship Canal, which runs through the city of Seattle, connects the fresh water body of Lake Washington with the salt water inland sea of Puget Sound. The Hiram M. Chittenden Locks accommodate the approximately 20-foot (6.1 m) difference in water level between Lake Washington and the sound. The canal runs east–west and connects Union Bay, the Montlake Cut, Portage Bay, Lake Union, the Fremont Cut, Salmon Bay, and Shilshole Bay, which is part of the sound.