Most of the land surrounding Prince William Sound is part of the Chugach National Forest, the second largest national forest in the U.S. Prince William Sound is ringed by the steep and glaciated Chugach Mountains. The coastline is convoluted, with many islands and fjords, several of which contain tidewater glaciers. The principle barrier islands forming the sound are Montague Island, Hinchinbrook Island, and Hawkins Island.
James Cook entered Prince William Sound in 1778 and named it Sandwich Sound, after his patron the Earl of Sandwich. The editors of Cook's maps changed the name to Prince William Sound, in honor of Prince William, who would later become King William IV.
In 1989, the oil tanker Exxon Valdez ran aground on Bligh Reef after leaving Valdez, causing a large oil spill, which resulted in massive damage to the environment, including the killing of around 250,000 seabirds, nearly 3,000 sea otters, 300 harbour seals, 250 bald eagles and up to 22 killer whales.