Gallatin County, Montana

Gallatin County is a county in Montana, United States, in the southwestern part of the state,
about 84 miles east of Butte. It had a population of 118,960 at the 2020 census, an estimated
128,740 by 2025, and covers 2,632 square miles (6,820 km2) centred near 45°34′N 111°10′W.

Bozeman is the county seat and the county’s largest city; its postal code is 59715. The county
holds 3 cities, 2 towns and 16 unincorporated communities, including 14 census-designated places,
and it runs on Mountain Time. Its FIPS code is 30031.

Towns & Villages in Gallatin County

Gallatin County has 21 named places on record: 5 incorporated cities and towns and 16
unincorporated communities, 14 of them census-designated places (CDPs) with their own population
counts. CDP stands for census designated place; Unincorp. covers communities with no census
boundary and no population count of their own.

Two entries need a note. Big Sky’s 3,591 residents are split between Gallatin and Madison
counties — the ski resort community straddles the line, and only the Gallatin side falls
inside this county. Bridger, the CDP around Bridger Bowl Ski Area on the east side of the
Bridger Range, is unrelated to the separate town of Bridger in Carbon County, roughly 250 miles
southeast; the two share a name only. The U.S. Census Bureau’s gazetteer also records dozens of
named mobile-home and trailer courts scattered through the Gallatin Valley — Alpine Trailer
Court, Wagon Wheel Trailer Court and similar — but these are private developments, not
independently recognized places, and are not counted among the 21 above.

ZIP Codes

• 59715 — Bozeman (the county’s main ZIP)
• 59718 — Bozeman/Four Corners, covering the west side of the Gallatin Valley
• 59717, 59719, 59771 and 59772 — Bozeman, mostly Montana State University and PO box
  codes rather than residential delivery
• 59714 — Belgrade
• 59741 — Manhattan
• 59752 — Three Forks
• 59758 — West Yellowstone
• 59716 — Big Sky
• 59730 — Gallatin Gateway

Amsterdam, Bridger, Churchill, Gallatin River Ranch, Hebgen Lake Estates, Hillman, King Arthur
Park, Logan, Maudlow, Ponderosa Pines, Sedan, Springhill and Willow Creek have no ZIP code of
their own; mail for these smaller communities is delivered under Bozeman’s, Belgrade’s or
Manhattan’s codes depending on location, and Hebgen Lake Estates and the far south end of the
county route through West Yellowstone’s 59758.

Geography

Gallatin County sits where the Gallatin, Madison and Jefferson valleys converge in
southwestern Montana, a landscape of broad irrigated farmland ringed by mountain ranges —
the Bridgers to the northeast, the Gallatins and the Spanish Peaks to the south, and the Tobacco
Roots to the west. Of the county’s 2,632 square miles, 2,603 are land and 29 are water, about 1.1
percent of the total, mostly Hyalite Reservoir and Hebgen Lake near the Yellowstone border. The
Gallatin River runs the length of the county from West Yellowstone north to Three Forks, where it
joins the Madison and Jefferson rivers to form the Missouri River at Missouri Headwaters State
Park.

Madison County lies to the west, Jefferson County to the northwest, Broadwater County to the
north, Meagher County to the northeast and Park County to the east. Park County, Wyoming and
Teton County, Wyoming border the county to the southeast, and Fremont County, Idaho to the
southwest, both across the Yellowstone National Park boundary. Madison County, Jefferson County, Broadwater County, Meagher County, Park County and Park County, Wyoming all border
Gallatin directly.

Demographics

Gallatin County had a population of 118,960 at the 2020 census, and the latest estimate puts
the county near 128,740 residents, making it Montana’s second most populous county after
Yellowstone County. Bozeman and Belgrade are by far the two largest communities, together holding
well over half the county’s population. Median household income runs about $75,418, higher than
Montana’s statewide figure of $70,804 (2023 ACS). Population density works out to roughly 46
people per square mile of land — dense by Montana standards, though still rural next to
most of the country, and concentrated almost entirely in the Gallatin Valley rather than the
mountainous south end of the county.

Economy & Local Life

Montana State University, based in Bozeman, is the county’s largest single employer and drives
much of its economy through research spending, construction and a steady flow of students and
staff. Bozeman Health runs the county’s main hospital campus and is a major regional health care
employer. Tourism dominates the south end of the county: Big Sky Resort, one of the largest ski
areas in the United States, and Bridger Bowl Ski Area near Bozeman draw winter visitors, while
West Yellowstone functions as a year-round gateway to Yellowstone National Park, whose west
entrance accounts for roughly half of all park visitors. The Gallatin Valley’s irrigated farmland
around Manhattan, Churchill and Amsterdam still supports wheat, barley and hay farming, alongside
a growing cluster of technology and manufacturing firms drawn to Bozeman in recent decades. Big
Sky’s Music in the Mountains and Bozeman’s Sweet Pea Festival, held each August, are the county’s
best-known annual events.

History

Meriwether Lewis named the Gallatin River in 1805 for Albert Gallatin, the U.S. Treasury
Secretary who helped organize the Lewis and Clark Expedition. Farmers settled the Gallatin Valley
starting in 1864 to supply grain to the gold camps around Virginia City, and Montana’s territorial
legislature created Gallatin County on 2 February 1865, one of the original nine counties of
Montana Territory. John Bozeman, for whom the county seat is named, helped found the settlement
the same year along a branch of the Bozeman Trail. The Northern Pacific Railroad reached Bozeman
in 1883, and Montana’s land-grant agricultural college, now Montana State University, opened
there in 1893. The county reached its present boundaries in 1978, when Montana dissolved
Yellowstone National Park’s separate county-equivalent status and divided its Montana portion
between Gallatin and Park counties.

Getting There

Interstate 90 crosses the county’s northern half through Belgrade, Bozeman and Three Forks. US
191 runs south from Bozeman through the Gallatin Canyon past Big Sky to West Yellowstone, and US
287 passes through Three Forks.

• Butte — about 84 miles west
• Billings — about 125 miles east
• Helena — about 90 miles northwest
• Yellowstone National Park’s west entrance — about 93 miles south

Bozeman Yellowstone International Airport, just north of Belgrade, is Montana’s busiest
airport and the nearest commercial air service for the whole county. No Amtrak line reaches
Gallatin County; the closest station is on the Empire Builder route in Whitefish, roughly 300
miles north.

Frequently Asked Questions

Where is Gallatin County located?
It sits in southwestern Montana where the Gallatin, Madison and Jefferson valleys meet, about 84
miles east of Butte, bordered by Madison, Jefferson, Broadwater, Meagher and Park counties.

What is the population of Gallatin County?
118,960 at the 2020 census, with a 2025 estimate near 128,740 — Montana’s second most
populous county.

How big is Gallatin County?
2,632 square miles (6,820 km2), of which 2,603 square miles are land.

What is the county seat of Gallatin County?
Bozeman, home to Montana State University, is the county seat and largest city.

How many towns and communities are in Gallatin County?
Five incorporated places — Bozeman, Belgrade, Three Forks, Manhattan and West Yellowstone
— plus 16 unincorporated communities, including 14 census-designated places such as Four
Corners, Big Sky and Churchill.

What ZIP codes does Gallatin County use?
59715 and 59718 for Bozeman, 59714 for Belgrade, 59741 for Manhattan, 59752 for Three Forks,
59758 for West Yellowstone, 59716 for Big Sky and 59730 for Gallatin Gateway.

Is Yellowstone National Park in Gallatin County?
Only its West Yellowstone gateway town sits in the county; the park itself lies mostly in
Wyoming, with a small Montana portion split between Gallatin and Park counties since 1978.

What is Gallatin County known for?
Montana State University, Big Sky Resort’s ski terrain, and West Yellowstone’s role as the
busiest entrance to Yellowstone National Park.

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