The Coghill River in Chugach National Forest flows southwest for 5 miles (8 km) from the terminus of Dartmouth Glacier to Coghill Lake, which is 4.7 miles (7.5 km) long, and then runs west-southwest for 3 miles (4.8 km) to College Fjord near Coghill Point, about 54 miles (87 km) west of Valdez and 32 miles (51 km) northeast of Whittier, Alaska. Dartmouth Glacier rises on Mount Castner’s south flank and flows 2.6 miles (4 km) southwest to its terminus. The river’s watershed is fed by several cirque glaciers—including Williams and Lafayette—and by snowfields on the western slope of the range that separates Unakwik Inlet from College Fjord. In 1908, a US Geological Survey team led by Ulysses S. Grant and Daniel F. Higgins—faculty at Northwestern University—named Dartmouth and Williams Glaciers for Dartmouth College (New Hampshire) and Williams College (Massachusetts). In 1947, Douglas Brown of the American Geographical Society named Lafayette Glacier for Lafayette College (Pennsylvania). During the Last Glacial Maximum, Prince William Sound was cloaked by the Cordilleran ice sheet. As the ice receded about 9,000 years ago, people migrated into the area. A prehistoric village site, Uqciuvit—about 10 miles (16 km) south-southwest of the Coghill River—indicates occupation beginning 4,400 years ago; advancing mountain glaciers during the Little Ice Age likely forced its abandonment. The glaciers of College Fjord were first noted in 1794 by Lieutenant Joseph Whidbey of Captain George Vancouver’s survey party. They were later observed by Samuel Applegate in 1887; by Edward F. Glenn, Joseph C. Castner, and Walter C. Mendenhall in 1898; by the Harriman Expedition in 1899; and by the US Geological Survey in 1908 and 1909. Henry Gannett of the Harriman Expedition produced a general map of the fjords and, with Grove Karl Gilbert, studied the glaciers. Later US Geological Survey teams, including Grant and Higgins, captured detailed photographs, descriptions, and a map that first depicted the Coghill River alongside Dartmouth and Williams Glaciers.

Grant and Higgins named the river, lake, and headland after their colleague, William Hawes Coghill, who performed assays on mineral collections for Grant. All three were Northwestern University faculty who spent summers with the US Geological Survey. Coghill studied mining and metallurgy at the Colorado School of Mines in Golden, Colorado, earning his degree in 1903. He then joined Northwestern as a professor while researching and conducting assays for mining clients. Later, he earned a doctorate and joined the US Bureau of Mines, publishing influential papers on metallurgy. He learned only later in life that several prominent Prince William Sound features bore his name. Coghill Lake supports more sockeye salmon than other Prince William Sound watersheds and historically produced the highest commercial returns. A record 1.1‑million sockeye were caught in 1982; by contrast, adult returns fell below 10,000 in 1990 and 1991. Several hypotheses have been proposed to explain the decline, the most likely being a reduction in macro-zooplankton caused by overforaging by rearing fry. Although the precise cause remains unknown, water sampling suggests the lake is nutrient limited, supporting a relatively low biomass of macro‐zooplankton vital for juvenile sockeye. To mitigate this, Pacific Northwest fishery managers boost zooplankton biomass through nutrient enrichment. The process promotes algal growth, which in turn supports a larger macro‐zooplankton population. Nutrient enrichment has proven effective in increasing a lake’s capacity to produce zooplankton for rearing sockeye salmon, resulting in greater smolt biomass, healthier out‑migrating juveniles, and ultimately higher adult returns. During a trial in Coghill Lake from 1993 to 1996, the seasonal mean phosphorus concentration increased 220% and zooplankton abundance rose 117% compared with pre‐enrichment levels, while the sockeye smolt population surged from an average of 264,000 to 941,000. These results underscore the potential of targeted nutrient enrichment to restore sockeye populations in nutrient‐limited lakes and support sustainable fisheries.

Russian explorers made the earliest recorded attempts to identify mineral resources in what is now the Chugach National Forest in the mid‑1800s. In 1848, Peter Doroshin, a mining engineer with the Russian-American Company, reported widespread gold-bearing gravels along the Kenai River. In 1898, prospectors bound for the Klondike were diverted by gold discoveries in the Prince William Sound–Kenai Peninsula area. Evidence of historical mining such as wing dams, hydraulic pipes, stamp mills and workings—is common throughout the forest, though most operations ceased by World War I. A brief resurgence occurred in 1934 when rising gold prices revived activity, only to see a dramatic decline at the onset of World War II. In the 1970s, renewed placer mining led to roughly 35 operations between 1972 and 1982, ranging from small suction dredges to large backhoe and dozer washing setups. A mineral resource inventory conducted from 1979 to 1982 by the US Geological Survey and the US Bureau of Mines combined a literature search with a four‑year field verification program. The search drew on historical files from federal agencies, the State of Alaska and active mining companies, while claim records were obtained from the Bureau of Land Management and the state. Additional insights came from interviews with miners and local experts, and field verification targeted areas newly exposed by retreating glaciers that had not been historically prospected. One highly mineralized zone was identified near Coghill Lake, about 3 miles (5 km) below Dartmouth Glacier’s terminus. Field verification detected gold in thin, poorly to moderately sorted alluvial gravels and in slate bedrock within the canyon of the northwest fork of the Coghill River. Three alluvium samples contained between 0.0004 and 0.0063 ounces (0.0113–0.1792 g) of gold per cubic yard, and nuggets up to 1/16 inch (1.6 mm) in diameter were recovered. These findings underscore the region’s potential for mineral future exploration. Read more here and here. Explore more of Coghill River and Dartmouth Glacier here: