The Flandreau post office opened in 1871, the earliest record of the town by name. Wikidata gives 1902. Another post office, Flandrau (1883), opened inside today’s city and later closed.
First census: 471 in 18802020 census: 2,372155 years
How did Flandreau get its name?
Flandreau was named in honor of Charles Eugene Flandrau, a judge in the territory and state of Minnesota.
How historic is Flandreau?
B+
More historic than 71% of U.S. towns, on its age, its old homes and the National Register.
Founding year: the first Flandreau post office (Blevins & Helbock, CC0). Wikidata: 1902. Name: Wikipedia, licensed CC BY-SA 4.0.
History grade
What drives Flandreau’s History grade
On its age, its old homes and the National Register, Flandreau is more historic than 71% of U.S. towns. Its share of homes from before 1940 holds the grade up; its age pulls it down.
B+
HistoryA character grade: shown, never part of Flandreau’s overall grade.
South Dakota towns list more on the Register than most of the country (a typical South Dakota town has 37.3 per 10,000 residents, the U.S. 2.4), so Flandreau’s 29.3 sits near the middle of its state (61% of South Dakota towns have fewer) while its 7 historic buildings outnumber those of 73% of U.S. towns.
How sure. Graded on any two of the three inputs instead, the letter would range from B− to A−. The pre-1940 share is a Census survey estimate (±5.5 points). The founding year is the first post office, not a stated founding date; Wikidata gives 1902.
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 Flandreau’s past
Read from the archive, the National Register and the record. The page puts what stands out first.
Fire insurance maps drew every building, what it was made of and what it was used for, so insurers could price the risk of fire. Pick a year, then a sheet.
1886Sheet 1 of 1
Edition
Sheets
BrickWoodStone
Sanborn Map Company, via the Library of Congress. Editions published in 1930 or earlier, which are in the public domain.
On the National Register
6 historic places in Flandreau
The country’s official list of buildings and places worth saving.
National Park Service, National Register of Historic Places. Photos from Wikimedia Commons, credited on each place’s page.
The story so far
Flandreau, in brief
Wikipedia doesn’t have a history of Flandreau yet. The photos, dates and memories neighbors add here are how it gets written.
Flandreau FLAN-droo is a city in and county seat of Moody County, South Dakota, United States. The population was 2,372 at the 2020 census. It was named in honor of Charles Eugene Flandrau, a judge in the territory and state of Minnesota. He is credited with saving the community of New Ulm, Minnesota, from destruction during conflict with the Sioux tribe in 1862. In 2015, the nearby federally recognized Flandreau Indian Reservation of Santee Sioux had planned to open the nation's first recreational marijuana lounge in a former bowling alley, close to its existing Royal River Casino and Hotel. Any tourists or non-tribal members using marijuana on tribal land risked state prosecution, so they…
Its first post office opened in 1871. Its population held steady between the last two censuses: 2,341 in 2010, 2,372 in 2020.
Intro from Wikipedia. Population: U.S. Census Bureau.
Timeline
Flandreau, 1871 to 1972
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.
The Flandreau post office opened in 1871, the earliest record of the town by name (U.S. post office records). Wikidata gives 1902.
How does Flandreau rank for history?
Flandreau is more historic than 71% 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.
What is on the National Register in Flandreau?
6 listings: 6 buildings, among them the St. Vincent's Hotel (listed 1983, the first). 7 historic buildings in all.
How old are the homes in Flandreau?
28% of Flandreau’s homes were built before 1940 (Census estimate, ±5.5 points), against a typical 10% for a South Dakota town; the median home was built in 1971.
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 (5), the Library of Congress (3), Wikidata (2), the National Register of Historic Places (6), Wikidata and Wikipedia for famous people, U.S. Geological Survey historical maps, U.S. Census counts (via Wikipedia), the US Post Offices dataset (Blevins & Helbock), the USGS Geographic Names Information System and Sanborn fire insurance maps (Library of Congress). Archive images are copied here with their credits and licenses, shown on each photo’s page. Refreshed monthly.
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