Eagle River Flats is a 2,471‐acre (1,000 ha) tidal flat and salt marsh at the mouth of Eagle River on Eagle Bay, on the eastern shore of Knik Arm at Joint Base Elmendorf–Richardson, about 10 miles (16 km) northeast of Anchorage and 7 miles (11 km) west of Eagle River, Alaska. The Dena’ina name for the river is Yukla-hitna (or Yukla Creek), recorded by the US Geological Survey in 1898 as meaning ‘Eagle Creek.’ In 1916 the Alaska Engineering Commission adopted the name Eagle River during construction of the Alaska Railroad. The river originates at Eagle Glacier and flows northwest 22 miles (35 km) to the community of Eagle River before turning west for about 10 miles (16 km) to Eagle Bay—a shallow bight roughly 4 miles (6.4 km) wide at its mouth. Knik Arm, a fjord extending north about 34 miles (55 km) as the northern arm of Cook Inlet, is bordered by the Chugach Mountains, which rise to elevations above 10,000 feet (3,962 m) to the east, and the Talkeetna Mountains, which exceed 8,800 feet (2,682 m) to the north. Glacial silt from the Knik and Matanuska Rivers has formed extensive tidal flats at the head of the fjord, where tides exceed 30 feet (9 m). Although the silt discourages invertebrates like clams and mussels, mobile marine mammals and migratory fish thrive. Five salmon species spawn in the Knik Arm watersheds: Chinook dominate in May and June in the Matanuska, followed by sockeye, chum, and pink salmon in summer, with coho from July to September. Eulachon spawn in the rivers, attracting harbor seals and, historically, beluga whales were observed in Eagle Bay from June to October. Eulachon were vital to the Dena’ina for food, oil, and trade with inland tribes.

Knik Arm is the traditional territory of the Dena’ina subgroup known as the K’enaht’ana, who now reside in the villages of Eklutna and Knik. Traditionally, the K’enaht’ana lived in permanent winter villages along productive salmon streams, lake mouths, or high bluffs above Knik Arm. Each village comprised one or more multi-family dwellings organized by kinship, while seasonal hunting and fishing camps—including those at the mouth of Eagle River—formed a network of satellite settlements. The annual cycle of subsistence began in spring after a lean winter. Some traveled to Eagle River’s mouth and beyond to harvest eulachon, seal, and beluga. Geese and other migratory waterfowl were snared in the wetlands. When the ice melted, beavers were harpooned and their meat smoked for preservation. Chinook salmon were prized for their early arrival and size. Fish were primarily caught on wooden platforms called tanik’edi—poles extending over salmon stream mouths—where individuals dip-netted fish while traps and weirs captured smaller salmon. Village leaders supervised harvests and regulated distribution. Salmon were dried, smoked, and stored for winter use, while some were fermented in birch bark baskets. Hunting larger animals such as moose and sheep began in late summer and fall. Just before freeze-up, hunters transported dried meat, fish, and skins in skin boats to the winter villages. In winter, people remained in their dwellings, subsisting on stored provisions. Visiting, trading, potlatching, and storytelling sustained social ties during the long months. Small game—including porcupine, hare, and ptarmigan—was taken with arrows, snares, clubs, deadfalls, and pitfalls, and entire families ice-fished local lakes for fresh fish. Oral histories record that extended winters or dwindling supplies sometimes led to food scarcity. The season ended with the return of waterfowl, eulachon, and salmon in spring, marking an annual cycle that persisted for thousands of years.

Captain James Cook first documented contact with the K’enaht’ana Dena’ina in 1778, entering the inlet in search of the Northwest Passage and trading at Tyonek and Point Possession. Later, William Bligh’s boat party explored Knik Arm without encountering the K’enaht’ana. By the 1780s, Russians and creoles had reached the Kenai Peninsula, yet little evidence exists of permanent European settlement or formal exploration of Knik Arm during Russian rule. The Russians exerted no direct control over the K’enaht’ana, though they introduced western trade goods. The K’enaht’ana became intermediaries between the Russians and interior Athabaskan tribes, exchanging furs for beads, copper, utensils, clothing, tea, and sugar. European contact also brought diseases—smallpox, influenza, measles, and tuberculosis—that decimated the Dena’ina and depopulated many villages. By the mid-1800s, the Russian Orthodox Church had taken root among the Dena’ina. After the 1867 Alaska Purchase, rapid demographic, economic, and social changes ended the K’enaht’ana’s isolation. A minor 1894 gold rush to Turnagain Arm and the 1910 Alaska Railroad—which established Anchorage—drew thousands to the region. The K’enaht’ana undertook seasonal wage labor and sold their salmon to local canneries. In 1940, Fort Richardson was built northeast of Anchorage, extending to Eagle River Flats on Knik Arm’s coast. It became the US Army’s Alaskan headquarters, with barracks for 500 soldiers, a rifle range, warehouses, a hospital, and officer quarters. Eagle River Flats was closed to subsistence hunting and has since served as a site for heavy artillery training. In 1981, an unusual high number of duck carcasses in the wetlands was linked to ingestion of elemental white phosphorus from smoke-producing shells. The toxic substance was found in near-surface sediments in the marsh and ponds, prompting the Army to suspend bombing and, after litigation, to clean up the site, institute ongoing monitoring, and impose firing restrictions. Read more here and here. Explore more of Eagle River Flats and Knik Arm here: