Watertown’s post office opened in 1879, and 18% of its homes were built before 1940
More historic than 68% of U.S. towns · #11 of 35 in South Dakota. What drives it
28 places in town are on the National Register, among them a historic district with 58 buildings. Below: 2 old photos and papers, maps from 1884 on, and the census since 1880.
Founding year: the first Watertown post office (Blevins & Helbock, CC0).The full story ↓
History grade
What drives Watertown’s History grade
On its age, its old homes and the National Register, Watertown is more historic than 68% of U.S. towns, #11 of 35 in South Dakota. Its National Register listings hold the grade up; its age pulls it down.
B+
HistoryA character grade: shown, never part of Watertown’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 Watertown’s 37.3 sits above most of its state (70% of South Dakota towns have fewer) while its 86 historic buildings outnumber those of 88% 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 (±2.7 points) is firm at this size. 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 Watertown’s past
Read from the archive, the National Register and the record. The page puts what stands out first.
Watertown was founded in 1879 as a rail terminus when the Chicago & Northwestern Railroad reactivated part of a line it had constructed to Lake Kampeska. The city was named after Watertown, New York, the hometown of brothers John E. and Oscar P. Kemp (grandfather of Jack Kemp), two of the city's founders. The town was originally planned to be called Kampeska.
During the 1880s, Watertown prospered as a transportation hub after the railroads had extended farther west. Along with several other cities, it had been a candidate for capital of the new state of South Dakota, losing to the more centrally located Pierre. The city's newspaper, the Watertown Public Opinion, began publishing in 1887.
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.
Every edition of the U.S. Geological Survey’s map of Watertown. Tap a year, or press play to watch the town change.
1969Watertown East sheet · 1:24,000
U.S. Geological Survey historical topographic maps (public domain), via Esri’s collection of the scans. The red ring marks the center of Watertown.
Every building
Watertown, building by building, 1884–1923
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.
The Watertown post office opened in 1879, the earliest record of the town by name (U.S. post office records).
How does Watertown rank for history?
Watertown is more historic than 68% of U.S. towns, #11 of 35 in South Dakota. 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 Watertown?
28 listings: 25 buildings, among them the Carnegie Free Public Library (listed 1976, the first), 1 historic district, the Watertown Commercial Historic District, with 58 contributing buildings, and 2 structures. 86 historic buildings in all.
How old are the homes in Watertown?
18% of Watertown’s homes were built before 1940 (Census estimate, ±2.7 points), against a typical 10% for a South Dakota town; the median home was built in 1979.
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 (2), Wikidata (1), the National Register of Historic Places (28), Wikipedia, 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.
1883
