​FLATHEADS, a tribe of North American Indians of Salishan stock. They formerly occupied the mountains of north-western Montana and the country around. They have always been friendly to the whites. Curiously enough they have not the ​custom, so general among American tribes, of flattening the heads of their infants. Father P. J. de Smet in 1841 founded among them a mission which proved the most successful in the north-west. With the Pend d’Oreille tribe and some Kutenais they are on a reservation in Montana, and number a few hundreds.