Coghill River starts at the terminus of Dartmouth Glacier, and flows southwest for 11 miles (17.7 km), through Coghill Lake to College Fjord, about 55 miles (89 km) west of Valdez, Alaska. The Dartmouth Glacier flows southwest from Mount Castner for 3.4 miles (5.5 km) to its terminus. The glacier was named in 1908 by Grant and Higgins of the U.S. Geological Survey, presumably for the college in Hanover, New Hampshire. The entire watershed lies within the Chugach National Forest.
During the last ice age, Prince William Sound was covered by the Cordilleran ice sheet until around 9,000 years ago. When the ice sheet receded, people began to migrate into the area, and evidence from a prehistoric village site called Uqciuvit near Coghill River suggests occupation from around 4,400 years ago. This village likely depended upon the salmon run in Coghill River for a portion of its annual subsistence needs.
Coghill Lake supports all five Pacific salmon species. Although finding all five species within one watershed is very unusual, the large numbers of sockeye salmon set Coghill apart from other watersheds in Prince William Sound. Coghill Lake has historically produced returns of over a million sockeye salmon, but since 1987 sockeye returns have steadily declined, and in 1990 and 1991 the returns fell below 10,000. Beginning in 1993, the productivity of the Coghill drainage was significantly increased by releasing hatchery-reared juvenile sockeye into the lake. Read more here and here. Explore more of Coghill River here: