The Plains post office opened in 1883, the earliest record of the town by name. Another post office, Horse Plains (1869), opened inside today’s town and later closed.
2020 census: 1,106143 years
How historic is Plains?
C
More historic than 33% of U.S. towns, on its age, its old homes and the National Register.
Founding year: the first Plains post office (Blevins & Helbock, CC0).
History grade
What drives Plains’ History grade
On its age, its old homes and the National Register, Plains is more historic than 33% of U.S. towns. Its share of homes from before 1940 holds the grade up; its National Register listings pull it down.
C
HistoryA character grade: shown, never part of Plains’ overall grade.
Montana towns list more on the Register than most of the country (a typical Montana town has 12.7 per 10,000 residents, the U.S. 2.4), so Plains’ 0.0 sits below most of its state (16% of Montana towns have fewer) while its 0 listings outnumber those of 23% of U.S. towns.
How sure. Graded on any two of the three inputs instead, the letter would range from D to C+. The pre-1940 share is a Census survey estimate (±6.9 points). The founding year is the first post office, not a stated founding date.
Founding year: the first post office (other dates in Quick answers). Homes: Census ACS 2020–24. National Register: National Park Service, May 2026 list; each listing counted once (boundary changes and added documentation belong to their listing), and a historic district counts its contributing buildings. How TownRatings grades history →
What stands out about Plains’ past
Read from the archive, the National Register and the record. The page puts what stands out first.
Wikipedia doesn’t have a history of Plains yet. The photos, dates and memories neighbors add here are how it gets written.
Plains (Salish: ncc̓kʷi) is a town in Sanders County, Montana, United States. The population was 1,106 at the 2020 census. It was founded as Horse Plains and sometimes called Wild Horse Plains, as the local Native Americans would winter their horses here to feed on the grasses in the valley. The name was later shortened to Plains when the US Postal Service established a presence in 1905. The town was established in 1883 as a Northern Pacific Railroad station.
Its first post office opened in 1883. Between the 2010 and 2020 censuses its population grew from 1,048 to 1,106 (+6%).
Intro from Wikipedia. Population: U.S. Census Bureau.
Timeline
Plains, 1869 to 1910
Woven from the archive, old maps, post office records, the National Register and the people born here.
Nothing in the archives for these yearsWeddings on Main Street, storms, parades, school pictures, the old store. If it’s in your family album, it belongs here.
Plains’s post office has been open since 1883. Another post office, Horse Plains, opened and closed inside today’s town.
Horse Plains
1869–1883
Plains
1883–today
18601940today
US Post Offices dataset (Blevins & Helbock, CC0). Places and cemeteries from the USGS Geographic Names Information System (2021).
Questions about Plains’ history
What year was Plains founded?
The Plains post office opened in 1883, the earliest record of the town by name (U.S. post office records).
How does Plains rank for history?
Plains is more historic than 33% of U.S. towns. The History grade combines the town’s founding era, the share of homes built before 1940 and its National Register listings. It’s a character grade, so it isn’t part of the overall grade. How it works.
How old are the homes in Plains?
16% of Plains’ homes were built before 1940 (Census estimate, ±6.9 points), against a typical 13% for a Montana town; the median home was built in 1978.
Founding dates: Wikidata, Wikipedia, the U.S. post office records of Blevins & Helbock (CC0) and the Census. Homes by year built: Census ACS 2020–24. National Register of Historic Places: National Park Service (list of May 22, 2026). Old photos, postcards and papers: Wikimedia Commons, the Library of Congress and other public archives, credited on each item’s page. Maps: U.S. Geological Survey historical topographic maps (via Esri) and Sanborn fire-insurance maps (Library of Congress). History text and census tables: Wikipedia (CC BY-SA 4.0). Places that used to be: USGS Geographic Names Information System (2021).
From Wikimedia Commons (4), the US Post Offices dataset (Blevins & Helbock) and the USGS Geographic Names Information System. Archive images are copied here with their credits and licenses, shown on each photo’s page. Refreshed monthly.
1910
2013
2005