The
Russian Petr Vasilii Malakhov reached the river at its confluence with the Yukon in 1838. The United States acquired Alaska after the American Civil War, but it was 1885 before US representatives Lieutenant
Henry Allen and Private Fred Fickett of the
United States Army ascended and explored the river. The discovery of
gold deposits by Johnnie Folger on the Middle Fork in 1893 on The Tramway bar led to a
gold rush in 1898; trading posts and mining camps, including Bettles, were rapidly developed on the upper river. In 1929,
Robert "Bob" Marshall explored the
North Fork of the Koyukuk River, and identified what he called the
Gates of the Arctic. In 1980 the
United States Congress designated 100 mi (164 km) of the North Fork of the Koyukuk River in the Brooks Range as the
Koyukuk Wild and Scenic River, which authorized certain levels of protection for the habitat. In 1994 the river flooded, sweeping away three villages, forcing the wholesale relocation of the population. ==Flora and fauna==