The Castor Township post office opened in 1834, the earliest record of the town by name. Eight smaller post offices, Castor (1834), Idalia (1889) and Avert (1890), opened inside today’s town and later closed.
2020 census: 4,674192 years
How historic is Castor Township?
B+
More historic than 72% of U.S. towns, on its age, its old homes and the National Register.
Founding year: the first Castor Township post office (Blevins & Helbock, CC0).
History grade
What drives Castor Township’s History grade
On its age, its old homes and the National Register, Castor Township is more historic than 72% of U.S. towns, #63 of 247 in Missouri. All 3 inputs are above most U.S. towns; its age ranks highest and its share of homes from before 1940 lowest.
B+
HistoryA character grade: shown, never part of Castor Township’s overall grade.
Missouri towns list about as much on the Register as the country (a typical Missouri town has 2.4 per 10,000 residents, the U.S. 2.4), so Castor Township’s 4.3 sits near the middle of its state (61% of Missouri towns have fewer) while its 2 listings outnumber those of 60% of U.S. towns.
How sure. Graded on any two of the three inputs instead, the letter would range from B to B+. The pre-1940 share is a Census survey estimate (±3.1 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 Castor Township’s 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 Castor Township yet. The photos, dates and memories neighbors add here are how it gets written.
Castor is an unincorporated community in the northwestern part of Filmore Township in Bollinger County, Missouri, United States. Castor is situated on the Castor River and is located approximately 16 miles west of Marble Hill.
Its first post office opened in 1834. Between the 2010 and 2020 censuses its population fell from 5,174 to 4,674 (-10%).
Intro from Wikipedia. Population: U.S. Census Bureau.
By decade
No old photos in the archives yet
Weddings on Main Street, storms, parades, school pictures, the old store. If it’s in your family album, it belongs here.
Be the first to add onePhotograph a print flat, in daylight, no flash.
Every edition of the U.S. Geological Survey’s map of Castor Township. Tap a year, or press play to watch the town change.
1934Bloomfield sheet · 1:62,500
U.S. Geological Survey historical topographic maps (public domain), via Esri’s collection of the scans. The red ring marks the center of Castor Township.
On the National Register
2 historic places in Castor Township
The country’s official list of buildings and places worth saving.
places listed
2
National Historic Landmarks
0
none yet
historic buildings protected
2
each building in a district counts
National Park Service, National Register of Historic Places. Photos from Wikimedia Commons, credited on each place’s page.
Famous people
Famous people close to Castor Township
Nobody well known was born in Castor Township itself, so here are the best known from just nearby.
The Castor Township post office opened in 1834, the earliest record of the town by name (U.S. post office records).
How does Castor Township rank for history?
Castor Township is more historic than 72% of U.S. towns, #63 of 247 in Missouri. 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 Castor Township?
12% of Castor Township’s homes were built before 1940 (Census estimate, ±3.1 points), against a typical 8.4% for a Missouri town; the median home was built in 1975.
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 U.S. Geological Survey historical maps, 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.
