Union Bay

Union Bay is a body of water located in Seattle, Washington. Part of Lake Washington, it is bounded by the Laurelhurst neighborhood to the north and the Montlake and Madison Park neighborhoods to the south. The Evergreen Point Floating Bridge, which carries State Route 520, crosses over a portion of the bay.

Marsh Island and Foster Island are located in Union Bay, and are connected to the mainland by the Arboretum Waterfront Trail and the Foster Island Trail. Union Bay ends at the eastern opening of the Montlake Cut, which connects Union Bay with Portage Bay to the west—this marks the beginning of the Lake Washington Ship Canal, which runs through Seattle and connects Lake Washington to Puget Sound.