It is generally considered to be the northern part of Puget Sound's Main Basin.
Admiralty Inlet's area is 437 square kilometres (169 sq mi), with a volume of 15,200 cubic metres (540,000 cu ft).
The first Europeans to find and map Admiralty Inlet were the Spanish of the 1790 expedition of Manuel Quimper.
[3] Today a great deal of maritime freight traffic passes through Admiralty Inlet to the major shipping ports at Seattle and Tacoma, and of United States Navy vessels to the Naval facilities in Puget Sound.
A tidal power project was canceled due to costs of monitoring wildlife.