established at Stevensville in 1850.  The Catholic priests called the river "St. Mary's".  However, the valley, river and mountain range are now named after
Montana's state flower, the Bitterroot.  The flower has a fleshy root and provided a steady food supply for the Indians long ago.

Chief Joseph, 250-400 Nez Perce warriors and their families passed through the valley in their futile flight to freedom in Canada, in what is known as the Nez Perce Indian War of 1877.  Their attempt to maintain their freedom and avoid the reservation was the only time the Nez Perce fought the whites.