The Treaty of Hellgate was signed in Hellgate on July 16, 1855 between Indian commissioner Isaac Stevens and the Native American tribes located in western Montana. The treaty was ratified by Congress, signed by President James Buchanan, and proclaimed on April 18, 1859.
The tribes involved in the signing of the treaty entailed the Bitteroot Salish, Pend d'Oreille, and the Kootenai. The tribes negotiated the Hellgate treaty with the United States in 1855. From the start, treaty negotiations were plagued by serious translation problems. A Jesuit observer, Father Adrian Hoecken, said that the translations were so poor that "not a tenth of what was said was understood by either side". But as in the meeting with Lewis and Clark, the pervasive cross-cultural miscommunication ran even deeper than problems of language and translation. Tribal people came to the meeting assuming they were going to formalize an already-recognized friendship. Non-Indians came with the goal of making official their claims to native lands and resources. Isaac Stevens, the new governor and superintendent of Indian affairs for Washington Territory, was intent on obtaining cession of the Bitterroot Valley from the Salish. Many non-Indians were already well aware of the valley's potential value for agriculture and its relatively temperate climate in winter. Due to the resistance of Chief Victor (Many Horses), Stevens ended up inserting into the treaty complicated (and doubtless poorly translated) language that defined the Bitterroot Valley south of Lolo Creek as a "conditional reservation" for the Salish. Victor put his X mark on the document, convinced that the agreement would not require his people to leave their homeland. No other word came from the government for the next fifteen years, so the Salish assumed that they would indeed stay in their Bitterroot Valley forever.
Based on the terms of the accord, the Native Americans were to relinquish their territories to the United States government in exchange for payment installments that totaled $120,000 dollars. The territories in question entailed everything from the main ridge of the Rocky Mountains at the 49th parallel to the Kootenai River and Clark Fork to the divide between the St. Regis River and the Coeur d'Alene River. From there, the ceded territories also extend to the southwestern fork of the Bitterroot River and up to Salmon River and Snake River. The treaty was ratified on March 8, 1859.