The Gulf of Alaska is an arm of the Pacific Ocean defined by the curve of the southern coast of Alaska, stretching from the Alaska Peninsula and Kodiak Island in the west to the Alexander Archipelago in the east, where Glacier Bay and the Inside Passage are to be found.

The entire shoreline of the Gulf is a rugged combination of forest, mountain, and a number of tidewater glaciers. The coast is also heavily indented, with Cook Inlet and Prince William Sound the two largest connected bodies of water, but also including Yakutat Bay and Cross Sound.

Meteorologically, the Gulf is a great generator of storms. In addition to dumping vast quantities of snow and ice on southern Alaska, resulting in some of the largest concentrations south of the Arctic Circle, many of the storms move south along the west coast of Canada and the United States, sometimes reaching as far as Mexico. Much of the seasonal rainfall in Washington, Oregon, and especially California comes from the Gulf of Alaska.