The main range of the Rocky Mountains separates that part which is drained west into the'Columbia river and the Pacific Ocean from that which is drained east into the Missouri and Mississippi rivers and the Gulf of Mexico, and from a very small part which is drained north-east into Hudson Bay; the water-parting which in Montana separates the drainage into Hudson Bay from the drainage into the Gulf of Mexico crosses only the north-west region of Teton county.
Long built in1902-1905by the co-operative Grass Valley-Frenchtown Irrigation Company, and the Teton Co-operative Canal Company in 1906 began work on a diversion canal from the Teton River, whose waters are to be stored by a dam 62 ft.
Among them are: the Huntley project in Yellowstone county, begun in 1904 and practically completed in 1908, covering land formerly in the Crow Indian reservation, the irrigable area being 28,921 acres; the Lower Milk river project (and the subsidiary St Mary project), in Chouteau, Valley and Teton counties, by which the water of St Mary river 1 is stored and diverted to the headquarters of the Milk river to irrigate an area of 300,000 acres; the Sun river project (Teton, Lewis and Clark, Chouteau and Cascade counties), by which, as the ordinary flow of that river is already utilized for irrigation, the flood waters are stored and carried to the higher bench lands of the district; in Montana (Dawson county) and North Dakota (McKenzie county), the Lower Yellowstone project; and the Blackfeet project, to irrigate the Blackfeet reservation in Teton county.
The Piegans, with small remnants of a few other tribes, numbering (1900) about 2060, occupy the Blackfeet reservation in the north-west of Teton county, the Crows, numbering 1857, occupy the Crow reservation in the south central part of the state; the Salish, with small remnants of the Pend Oreille, the Spokan, the Lower Kalispell and the Kutenai, numbering 1837, occupy the Flathead reservation in the north of Missoula and the south of Flathead county; Assiniboins and others of Sioux stock, numbering about 1793, occupy Fort Peck reservation in the south-east of Valley county: Atsina and Assiniboins, numbering about 1429, occupy Fort Belknap reservation in the east of Chouteau county; and the Northern Cheyennes, numbering about 1357, occupy Northern Cheyenne reservation in the south-east of Rosebud county.
The finest examples of this kind are the moraines about Jackson Lake on the basin floor east of the Teton Range (Grand Teton, 13,747 ft.), a superb north-south range which lies close to the meridional boundary line between Wyoming and Idaho.