Highway 66 in the U.S. State

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Montana

Montana

Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...

 is a route running northerly from an intersection with U.S. Route 191

U.S. Route 191

U.S. Route 191 is a spur of U.S. Route 91 that has two branches. The southern branch runs for 1,465 miles from Douglas, Arizona on the Mexican border to the southern part of Yellowstone National Park. The northern branch runs for 440 miles from the northern part of Yellowstone National Park to...

 in far southwestern Phillips County

Phillips County, Montana

-National protected areas:* Bowdoin National Wildlife Refuge* Charles M. Russell National Wildlife Refuge * Hewitt Lake National Wildlife Refuge* UL Bend National Wildlife Refuge* Upper Missouri River Breaks National Monument -Demographics:...

 to the town of Fort Belknap

Fort Belknap Agency, Montana

Fort Belknap Agency is a census-designated place in Blaine County, Montana, in the United States. As of the 2000 census, the CDP population was 1,262.-Geography:Fort Belknap Agency is located at ....

 in Blaine County

Blaine County, Montana

-National protected areas:* Black Coulee National Wildlife Refuge* Nez Perce National Historical Park * Upper Missouri River Breaks National Monument -Economy:The main industry in Blaine County is Agriculture...

, a distance of approximately 50 miles (80.5 km). Approximately the northern 40 miles (64.4 km) of the route is within the boundaries of the Fort Belknap Indian Reservation

Fort Belknap Indian Reservation

The Fort Belknap Indian Reservation is a semi-autonomous Native American-governed territory covering 1,014.064 sq mi , and is located in north central Montana. This includes the main portion of their homeland, as well as off-reservation trust land. It is shared by two Native American tribes, the...

, and much of the road is aligned on a straight, north–south axis. The southern end of the road runs near the western edge of the Little Rocky Mountains

Little Rocky Mountains

The Little Rocky Mountains, also known as the Little Rockies, are a group of buttes, roughly 765 km2 in area, located towards the southern end of the Fort Belknap Agency in Blaine County and Phillips County in north-central Montana...

, near the former mining town of Landusky.