Lacey V. Murrow Memorial Bridge, Floating road bridge on Lake Washington, Seattle, United States

The Lacey V. Murrow Memorial Bridge is a floating highway bridge built from concrete pontoons that crosses Lake Washington, linking Seattle to Mercer Island via Interstate 90. The structure consists of a series of hollow concrete boxes resting on the water surface, carrying the eastbound lanes of the highway while a second parallel bridge handles westbound traffic.

The original Lake Washington Floating Bridge opened on July 2, 1940, built for about $9 million after engineer Homer Hadley's 1921 proposal and George Lightfoot's lobbying. It closed on June 23, 1989, for renovation, and on November 25, 1990, a 2,790-foot section sank after water filled pontoons whose watertight doors had been removed. The replacement opened in 1993.

The bridge is named for Lacey V. Murrow, the second director of the Washington State Highway Department, who backed Homer Hadley's floating-bridge proposal and had it built; he was also a decorated bomber pilot and the elder brother of broadcaster Edward R. Murrow. The name was given in 1967, a year after his death. The bridge's arrival turned Mercer Island from a summer resort into a Seattle suburb.

Crossing takes a few minutes by car and offers open views of the water surface and surrounding hills from certain points. Traffic may slow during rush hours, especially during morning hours heading east and in the afternoon returning toward Seattle.

The concrete pontoons move slightly with the waves of the lake, so the roadway gently shifts when larger boats pass nearby or during windy conditions. The design served as a model for other floating bridge projects worldwide and attracted engineers from different countries seeking similar solutions for deep water crossings.