Gulf, southern Alaska, U.S. Situated between the Alaska Peninsula and the Alexander Archipelago , it receives the Susitna and Copper rivers.
Ports on the gulf include Anchorage , Seward, and Valdez; the last is North America's northernmost ice-free harbour and the Trans-Alaska Pipeline 's terminal. Capt. James Cook , its European discoverer, entered the gulf in 1778 and proceeded as far north as Prince William Sound.