Prince William Sound is a sound of the Gulf of Alaska on the south coast of the U.S. state of Alaska. It is located on the east side of the Kenai Peninsula. The coastline is convoluted, with many islands and fjords, several of which contain tidewater glaciers. 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. Photo by Carol Highsmith.