Big Horn County, Montana

Big Horn County is a county in Montana, United States, in the south-central part of the state, home to the Little Bighorn Battlefield and most of the Crow Indian Reservation. It had a population of 13,124 at the 2020 census and covers 5,015 square miles (12,990 km2) centred near 45°26′N 107°29′W.

Hardin is the county seat; its postal code is 59034. The county contains one city, one town, eight census-designated places, and seven smaller unincorporated communities, all within the Mountain time zone.

Towns & Villages in Big Horn County

Big Horn County has only two incorporated places — Hardin (a city) and Lodge Grass (a town) — plus eight census-designated places (CDPs, unincorporated but tracked by the Census Bureau) and a scattering of smaller unincorporated communities across the Crow and Northern Cheyenne reservations. Several settlements once listed on this page — including Dillon, Bannack, Glendale, Wisdom and Lima — actually belong to Beaverhead County, Montana, more than 250 miles to the west, and have been removed.

Note for readers arriving from a search for a different Big Horn County: Wyoming also has its own Big Horn County (seat Basin), which borders this one to the southwest. This page covers Big Horn County, Montana, seat Hardin.

ZIP Codes

• 59034 — Hardin (also serves the surrounding ranch country)
• 59022 — Crow Agency
• 59050 — Lodge Grass
• 59016 — Busby
• 59089 — Wyola
• 59066 — Pryor
• 59031 — Garryowen
• 59035 — Fort Smith
• 59075 — St. Xavier
• 59025 — Decker

Small communities such as Muddy, Forty Mile Colony, Aberdeen, Benteen, Dunmore, Kingley and Toluca have no post office of their own and are served by the nearest listed ZIP code.

Geography

Big Horn County lies on the plains and badlands of south-central Montana, cut by the Bighorn River as it flows north to join the Yellowstone River near Custer. The Bighorn and Pryor mountain ranges rise along the county’s western edge, and the Bighorn Canyon National Recreation Area, formed behind Yellowtail Dam, sits in the county’s southern reach near Fort Smith. Of the county’s 5,015 square miles, 4,995 square miles are land and 19 square miles are water.

Big Horn County borders Carbon County to the west, Yellowstone County to the northwest, Treasure County to the north, Rosebud County to the northeast, Powder River County to the east, Sheridan County, Wyoming, to the south, and Big Horn County, Wyoming, to the southwest.

Demographics

The 2020 census counted 13,124 residents, a population density of roughly 2.6 people per square mile of land. Hardin and Crow Agency are the two largest communities. About 67.0% of residents identified as American Indian or Alaska Native and 26.8% as White, with 33.4% of the population under age 18 — among the youngest age profiles of any Montana county. Median household income trails the Montana median of $70,804 by a wide margin, a gap tied to the limited wage-job base on the Crow and Northern Cheyenne reservations that cover most of the county.

Economy & Local Life

Coal underlies much of the Crow Reservation, and coal mining and mineral leasing are major sources of tribal and county revenue, alongside cattle ranching and dryland farming of sugar beets, alfalfa and small grains along the Bighorn and Little Bighorn river valleys. Little Big Horn College, a tribal college chartered by the Crow Tribe, is based in Crow Agency. Fort Smith serves as the gateway to Bighorn Canyon National Recreation Area and Yellowtail Dam, drawing anglers and boaters to Bighorn Lake. The Little Bighorn Battlefield National Monument, near Garryowen and Crow Agency, is the county’s best-known visitor site and hosts the annual Custer’s Last Stand Reenactment near the battle’s late-June anniversary.

History

Big Horn County traces to an 1865 territorial county designation but was not organized in its present form until January 13, 1913, carved from Custer and Yellowstone counties. Its name, like the river and mountain range that cross it, comes from the bighorn sheep once common along the Bighorn River canyon. The county’s best-known historical event predates its organization by decades: the Battle of the Little Bighorn, fought June 25–26, 1876, between the U.S. 7th Cavalry under Lieutenant Colonel George Armstrong Custer and a combined force of Lakota, Northern Cheyenne and Arapaho warriors, took place on what is now the county’s Crow Reservation land.

Getting There

Interstate 90 runs the length of the county past Hardin and Crow Agency; U.S. Highway 87 and U.S. Highway 212 and Montana Highways 47, 313 and 314 connect the smaller communities.

• Billings — about 45 miles northwest via I-90
• Sheridan, Wyoming — about 60 miles south via I-90
• Miles City — about 100 miles east via I-94
• Bighorn Canyon National Recreation Area (Fort Smith) — about 45 miles south of Hardin

Billings Logan International Airport, roughly 45 miles northwest of Hardin, is the nearest commercial airport.

Frequently Asked Questions

Where is Big Horn County, Montana?
It is in south-central Montana, along the Bighorn River between Billings and the Wyoming border.

What is the population of Big Horn County?
13,124 people, per the 2020 census.

How big is Big Horn County?
5,015 square miles (12,990 km2), of which 4,995 square miles are land.

What is the county seat of Big Horn County?
Hardin is the county seat.

How many towns are in Big Horn County?
Two incorporated places — Hardin and Lodge Grass — plus eight census-designated places and several smaller unincorporated communities.

What ZIP codes are in Big Horn County?
Ten ZIP codes, led by 59034 (Hardin), 59022 (Crow Agency) and 59050 (Lodge Grass).

Is Big Horn County the same as Big Horn County, Wyoming?
No. This page covers Big Horn County, Montana, seat Hardin. Big Horn County, Wyoming, seat Basin, is a separate county bordering it to the southwest.

More counties in this state: Towns and villages in Montana.