Yellowstone County, Montana

Yellowstone County is a county in Montana, United States, centred where the Yellowstone River bends from southwest to northeast across the plains east of the Beartooth foothills. It had a population of 164,731 at the 2020 census, the largest of any Montana county, and covers 2,649 square miles (6,860 km2) centred near 45°56′N 108°17′W.

Billings is the county seat, and its postal code is 59101. The county has two cities, one town, and roughly a dozen census-designated places, plus scattered unincorporated communities along the river valley. Yellowstone County runs on Mountain Time and carries FIPS code 30111.

Towns & Villages in Yellowstone County

Billings anchors the county on the north bank of the Yellowstone River; Laurel sits 15 miles west along the same valley. Most other communities are small farm towns or river-bottom hamlets strung along I-90 and the Yellowstone River.

ZIP Codes

• 59101–59107 — Billings (also serves Lockwood)
• 59044 — Laurel
• 59015 — Broadview
• 59088 — Worden
• 59079 — Shepherd
• 59037 — Huntley
• 59006 — Ballantine
• 59024 — Custer
• 59064 — Pompeys Pillar
• 59057 — Molt

Acton, Nibbe, Mountain View Colony, Bull Mountain, Rimrock, and Yegen have no ZIP of their own; mail there is routed through Billings or the nearest listed office.

Geography

The Yellowstone River enters the county from the southwest and exits at the northeast corner, splitting the county between the irrigated bottomland along its banks and drier bench land above. The Rimrocks, a line of sandstone cliffs, wrap the north side of Billings and gave the surrounding formation its name; the Bull Mountains rise in the county’s northern reaches. Of the county’s total area, 2,633 square miles are land and 16 square miles are water.

Yellowstone County borders seven other Montana counties: Musselshell to the north, Rosebud to the northeast, Treasure to the east, Big Horn to the southeast, Carbon to the southwest, Stillwater to the west, and Golden Valley to the northwest.

Demographics

The county’s population was 164,731 at the 2020 census; the 2024 estimate put it near 172,000, still Montana’s most populous county by a wide margin. Billings and Laurel are its two largest communities. Median household income runs above the Montana state figure of $70,804, reflecting Billings’s role as the state’s largest trade and medical hub. Population density is about 62 people per square mile, concentrated heavily in and around Billings.

Economy & Local Life

Healthcare and trade drive the county’s economy: Billings Clinic and Intermountain Health each employ more than 1,000 people and anchor a growing medical corridor that draws patients from across Montana and Wyoming. First Interstate Bank and Kampgrounds of America are both headquartered in Billings, and food processing plants for Coca-Cola, Franz Bakery, and Meadow Gold operate in the city. Outside the city, farming and cattle ranching remain the mainstay along the Yellowstone bottomland. MontanaFair, held every August at MetraPark in Billings, is the county’s largest annual gathering.

History

Yellowstone County was created on February 26, 1883, and organized on May 1, 1883, carved from a much larger Montana Territory county before statehood. It takes its name from the Yellowstone River, whose yellow sandstone cliffs upstream gave the river, and later the county, its name. Billings was founded in 1882 as a railhead for the Northern Pacific Railway and grew into the county’s dominant city; the Northern International Livestock Exposition, launched in the early 20th century, remains an annual fixture drawing ranchers from across the region.

Getting There

Interstate 90 and Interstate 94 both run through the county, meeting near Billings, along with US 87 and US 212.

• Laurel — 15 miles west of Billings
• Hardin — 45 miles southeast of Billings
• Roundup — 50 miles north of Billings
• Columbus — 40 miles southwest of Billings

Billings Logan International Airport, inside the city, is the county’s commercial airport and the largest in Montana by passenger traffic. Amtrak does not serve Billings; the nearest station is in Havre, about 260 miles north on the Empire Builder line.

Frequently Asked Questions

Where is Yellowstone County?
It sits in south-central Montana, straddling the Yellowstone River east of the Beartooth Mountains.

What is the Billings postcode?
Billings uses ZIP codes 59101 through 59107, depending on the neighborhood.

Is Billings the county seat?
Billings is the county seat and the largest city in Montana.

What is Yellowstone County’s population?
It had a population of 164,731 at the 2020 census, the most of any Montana county.

Where does the county’s name come from?
It is named for the Yellowstone River, whose yellow sandstone cliffs upstream gave the river its name.

What is the nearest airport?
Billings Logan International Airport, inside the city limits, is the county’s commercial airport.

Does Amtrak serve the county?
No. The nearest Amtrak station is in Havre, about 260 miles north.

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