As the Corps of the Discovery continued up the Missouri River in July 1805, Sacajawea, the Lemhi Shoshone Indian who accompanied the expedition, began recognizing her people’s territory. Eager to meet the Shoshone, William Clark and four men separated from the main party in search of them. On the morning of July 25, 1805, Clark and his small party arrived at the Three Forks of the Missouri River, having failed to find any Shoshone Indians.

Reaching the headwaters of the Missouri River was one of the main objectives of the expedition. They had traveled an estimated 2,500 miles since departing Camp Dubois in May 1804. Now the challenge ahead was figuring out which river would provide the best route. The middle and northern forks are the same size at about 90 yards wide, while the south fork is 70 yards across and falls 400 yards below the middle fork. Clark, judging on the greater flow and more direct path to the western mountains, chose the northern fork.

After Clark chose his path, he and the four men continued on upstream of the northern fork through a valley searching for any signs of Indians. Two days later, on July 27, Lewis and the main party arrived at the Three Forks; Clark also returned to the headwaters that day. The captains decided to remain at the Three Forks for a few days in order to rest the men. During this time, Lewis and Clark named the three rivers. The South Fork they named after Albert Gallatin (Secretary of the Treasury), the Middle Fork after James Madison (Secretary of State), and the North Fork was named in honor of President Thomas Jefferson.

On July 30, 1805, the Corps departed from the Three Forks and continued up the Jefferson River. About two weeks later, on August 12, Lewis reached today’s Trail Creek near Lemhi Pass and determined that spot as “the most distant fountain of the waters of the mighty Missouri in surch of which we have spent so many toilsome days and wristless nights.”

Today, the area of the Three Forks is a part of the Missouri Headwaters State Park, located off of Interstate 90, near the town of Three Forks, Montana.

Researched, written, and narrated by University of West Florida Public History Student Johnathan Jones.

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