Weston County is a county in Wyoming, United States, in the state’s northeastern corner along
the South Dakota line. It had a population of 6,838 at the 2020 census, an estimated 6,826 by
2024, and covers 2,398 square miles (6,211 km2) of land centred near 43°50′N 104°34′W.
Newcastle is the county seat and only city; its postal code is 82701. The county holds 1 city,
1 incorporated town and 5 smaller communities, and it runs on Mountain Time. Its FIPS code is
56045. Wyoming has no civil townships, so places here are grouped only by incorporation status.
Towns & Villages in Weston County
Weston County has 7 named places on record: 2 incorporated (Newcastle and Upton), 2 census
designated places, and 3 unincorporated communities with no local government of their own. CDP
stands for census designated place; Unincorp. covers crossroads and rural communities with no
formal boundary.
| Place | Type | Pop. | ZIP |
|---|---|---|---|
| Newcastle | City · seat | 3,374 | 82701 |
| Upton | Town | 898 | 82730 |
| Osage | CDP | 151 | 82723 |
| Hill View Heights | CDP | 144 | — |
| Buckhorn | Unincorp. | — | — |
| Four Corners | Unincorp. | — | — |
| Clareton | Unincorp. | — | — |
ZIP Codes
- 82701 — Newcastle (the county’s most populous ZIP)
- 82730 — Upton
- 82723 — Osage
Hill View Heights, Buckhorn, Four Corners and Clareton have no ZIP code of their own; mail
there is delivered under the nearest incorporated town’s code.
Geography
Weston County sits in Wyoming’s northeastern corner, at the southwestern edge of the Black
Hills. Of its 2,400 square miles, 2,398 are land and 1.9 are water, about 0.08 percent —
the county has no large natural lake, and its surface water is mostly small creeks. Part of the
Black Hills National Forest covers the county’s northeast, and the Thunder Basin National
Grassland reaches into its western reaches.
Crook County lies to the north, Campbell County to the west, Niobrara County to the south, and
Converse County to the southwest. Three South Dakota counties border the county’s eastern edge:
Lawrence County to the northeast, Pennington County to the east, and Custer County to the
southeast. Crook County, Campbell County, Niobrara County, Converse County, Lawrence County, Pennington County and Custer County all border
Weston directly.
Demographics
Weston County had a population of 6,838 at the 2020 census, and the latest estimate puts the
county near 6,826 residents, essentially flat over the period. Newcastle and Upton are by far
the two largest communities, together holding roughly two-thirds of the county’s population.
Median household income runs $89,509, above Wyoming’s statewide figure of $72,415 (2023 ACS).
Population density works out to roughly 2.9 people per square mile of land, among the more
sparsely settled counties in the state.
Economy & Local Life
Mining, quarrying, and oil and gas extraction employ the most workers in the county, about
588 people, followed by health care and social assistance at 340 and retail trade at 292.
Extractive industry has anchored the local economy since coal was first found north of Newcastle
in 1887, and today’s mining sector reflects continued oil, gas and industrial-mineral
production in the surrounding basin. Newcastle’s schools, county offices and the Weston County
Library are the town’s other steady employers.
History
The Wyoming Territory legislature created Weston County on 12 March 1890, carving it out of
Crook County. It was named for Jefferson Weston, a geologist and surveyor who, with Frank
Mondell, found rich coal deposits north of Newcastle in 1887, prompting a railroad to be built
through the area. Newcastle was founded in 1889 as that railroad’s mining town, named after
Newcastle-upon-Tyne, England, a coal-shipping port. President Theodore Roosevelt visited the
town in 1903, and Mondell, its first mayor, went on to represent Wyoming in the U.S. House.
Cambria, north of Newcastle, grew into a company coal-mining town after Mondell found
high-grade anthracite there in 1887; it peaked near 1,400 residents around 1904 and produced
about 13 million tons of coal before the vein thinned and the company blew its closing whistle
for the last time on 15 March 1928. Cambria and the nearby camp of Tubb Town are both ghost
towns today.
Getting There
U.S. Highways 16, 20 and 85 cross the county through Newcastle; no interstate runs through
Weston County. Wyoming Highways 116, 450 and 585 connect the smaller communities.
- Rapid City, South Dakota — about 78 miles northeast via US 16
- Gillette, Wyoming — about 77 miles west
- Casper, Wyoming — about 185 miles west
Mondell Field Airport in Newcastle, named for Frank Mondell, handles general aviation; the
nearest commercial airline service is Rapid City Regional Airport in South Dakota. Wyoming has
no Amtrak service, and no station is within reasonable driving distance of the county.
Frequently Asked Questions
Where is Weston County located?
It sits in Wyoming’s northeastern corner along the South Dakota line, bordered by Crook,
Campbell, Niobrara and Converse counties in Wyoming and Lawrence, Pennington and Custer counties
in South Dakota.
What is the population of Weston County?
6,838 at the 2020 census, with a recent estimate near 6,826.
How big is Weston County?
2,400 square miles (6,211 km2), of which 2,398 square miles are land.
What is the county seat of Weston County?
Newcastle, founded in 1889, is the county seat and the county’s only city.
How many towns and cities are in Weston County?
Two incorporated places, Newcastle and Upton, plus the census-designated places Osage and Hill
View Heights and the unincorporated communities Buckhorn, Four Corners and Clareton.
What ZIP codes does Weston County use?
82701 for Newcastle, 82730 for Upton and 82723 for Osage.
What is Weston County known for?
The 1887 coal discovery that founded Newcastle and the Cambria mining camp, and its position at
the southwestern edge of the Black Hills.
More counties in this state: Towns and villages in Wyoming.