Elliott Bay is a part of the Central Basin region of Puget Sound. It is in the U.S. state of Washington, extending southeastward between West Point in the north and Alki Point in the south. Seattle was founded on this body of water in the 1850s and has since grown to encompass it completely. The waterway it provides to the Pacific Ocean has served as a key element of the city's economy, enabling the Port of Seattle to become one of the busiest ports in the United States.

Puget Sound is a sound on the northwestern coast of the U.S. state of Washington. It is a complex estuarine system of interconnected marine waterways and basins. A part of the Salish Sea, Puget Sound has one major and two minor connections to the Strait of Juan de Fuca, which in turn connects to the open Pacific Ocean. The major connection is Admiralty Inlet; the minor connections are Deception Pass and the Swinomish Channel.