Each edition grades its towns against each other only.
More historic than 70% of U.S. towns. What drives it
Its Register listings are the Trinity Episcopal Church, the McKenzie-Cassels House and the First Presbyterian Church of Groton. Below: 1 old photo or paper, maps from 1884 on, and the census since 1890.
The Groton post office opened in 1881, the earliest record of the town by name. Wikidata gives 1888.
More historic than 70% of U.S. towns, on its age, its old homes and the National Register.
On its age, its old homes and the National Register, Groton is more historic than 70% of U.S. towns. Its share of homes from before 1940 holds the grade up; its age pulls it down.
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 Groton’s 23.7 sits near the middle of its state (57% of South Dakota towns have fewer) while its 4 historic buildings outnumber those of 68% of U.S. towns.
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 →
Read from the archive, the National Register and the record. The page puts what stands out first.
The first neighbors to add old photos shape how Groton’s history is told.
Every edition of the U.S. Geological Survey’s map of Groton. Tap a year, or press play to watch the town change.
U.S. Geological Survey historical topographic maps (public domain), via Esri’s collection of the scans. The red ring marks the center of Groton.
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.
1884Sheet 1 of 1Sanborn Map Company, via the Library of Congress. Editions published in 1930 or earlier, which are in the public domain.
From Wikipedia’s history of Groton.
Groton was platted in 1881. The city was named after Groton, Massachusetts. A post office has been in operation at Groton since 1881.
Text from Wikipedia, licensed CC BY-SA 4.0.
Woven from the archive, old maps, post office records, the National Register and the people born here.
One decade in the archive so far: the 1930s. Scroll each row; tap a photo for its story.
No then-and-now pairs yet. Take a photo from the same spot as an old one and they appear here side by side.
Find the spot, match the angle, and add your photo. It becomes the first then-and-now pair on Groton’s page.
Retake this view · +15The 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.
Between 684 and 1,458 people in every census since 1890.
14 censuses, 1890–2020.
U.S. Census Bureau decennial counts, from the census table on Groton’s Wikipedia page.
The Groton post office opened in 1881, the earliest record of the town by name (U.S. post office records). Wikidata gives 1888.
Groton is more historic than 70% 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.
Three places: the Trinity Episcopal Church (listed 1983), the McKenzie-Cassels House (1986) and the First Presbyterian Church of Groton (2019).
30% of Groton’s homes were built before 1940 (Census estimate, ±10.0 points), against a typical 10% for a South Dakota town; the median home was built in 1975.
What the archives can’t tell you, neighbors can.
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), Wikidata (1), the National Register of Historic Places (3), 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.
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