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B−History
History · Seneca

Seneca’s post office opened in 1869, and 27% of its homes were built before 1940

More historic than 45% of U.S. towns. What drives it

Below: maps from 1894 on and the census since 1870.

1869first post office
0on the National Register
27%homes built before 1940
2famous people
Add an old photoShare a memory
Photo: TheWhitePelican · CC BY-SA 3.0
Quick answers

How Seneca began

When was Seneca founded?

1869

The Seneca post office opened in 1869, the earliest record of the town by name.

First census: 285 in 18702020 census: 2,230157 years

How historic is Seneca?

B−

More historic than 45% of U.S. towns, on its age, its old homes and the National Register.

What drives the grade ↓
Founding year: the first Seneca post office (Blevins & Helbock, CC0).The full story ↓
History grade

What drives Seneca’s History grade

On its age, its old homes and the National Register, Seneca is more historic than 45% of U.S. towns. Its share of homes from before 1940 holds the grade up; its National Register listings pull it down.

B−
HistoryA character grade: shown, never part of Seneca’s overall grade.
Founding era1869, from the first post office: founded 1850–1899, an older era than 37% of U.S. townsC+Homes built before 194026.6% of homes (±7.5) · typical MO town 8.4% · U.S. 8.4%A−National RegisterNo listings counted · typical MO town 2.4 per 10,000 · U.S. 2.4C−
All U.S. towns we grade (21,289)Ahead of 45%
NewerOlder

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 Seneca’s 0.0 sits below most of its state (23% of Missouri 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 C− to B. The pre-1940 share is a Census survey estimate (±7.5 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 Seneca’s past

Read from the archive, the National Register and the record. The page puts what stands out first.

A history waiting to be writtenNo old photos of Seneca are in the public archives yet. The rest are in attics and albums.Mapped building by building3 fire insurance maps, 1894 to 1914, drew every building in Seneca.
★ What stands out · Help out

Start Seneca’s collection

The first neighbors to add old photos shape how Seneca’s history is told.

Decades since 1900 with photos
00s10s20s30s40s50s60s70s80s90s
0 of 10 decades. The empty ones are waiting for someone’s album.
Share a family photoSign in to add one+10
Every building

Seneca, building by building, 1894–1914

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.

Seneca fire insurance map, 1894, sheet 11894Sheet 1 of 2
Edition
BrickWoodStone

Sanborn Map Company, via the Library of Congress. Editions published in 1930 or earlier, which are in the public domain.

The story

How Seneca came to be

From Wikipedia’s history of Seneca.

Read it all →

Seneca was platted by European Americans in 1869, following the Civil War. The city was named for the Seneca Nation, one of the Six Nations of the Iroquois League, or Haudenosaunee, who had been historically based in New York and south of the Great Lakes.

In the 1830s, many of the Seneca people still in the East had been pushed west of the Mississippi River into Indian Territory, which included parts of present-day Missouri, Kansas and Oklahoma. "This tribe was moved to the Indian Territory not many miles west of town. The word is a corruption of the Dutch word "Sinnekaas," a term applied to them."

A post office called Seneca has been in operation since 1869.

Text from Wikipedia, licensed CC BY-SA 4.0.

Timeline

Seneca, 1869 to 1949

Woven from the archive, old maps, post office records, the National Register and the people born here.

  1. 19th century
  2. 1869Post officeThe Seneca post office opens
  3. 20th century
  4. 1934Born hereRonald L. Watts is born here
  5. 1936Born hereMorris Watts is born here
  6. 1949On the mapFirst mapped by the U.S. Geological Survey
By decade

Seneca, decade by decade

Today10 recent
Milnot in2009Milnot inLantsFeedMemorial022009LantsFeedMemorial02LantsFeedMemorial012009LantsFeedMemorial01Welcome to2008Welcome toSeneca Old Schoolhouse2008Seneca Old SchoolhouseSeneca MO City Hall2008Seneca MO City HallDowntown2008DowntownCreek in2008Creek inCaboose and School House2008Caboose and School HouseBridge Over Creek 012008Bridge Over Creek 01
On the map

Seneca on the map, 1949 to 1978

Every edition of the U.S. Geological Survey’s map of Seneca. Tap a year, or press play to watch the town change.

Seneca on the 1949 USGS mapSeneca on the 1950 USGS mapSeneca on the 1978 USGS map1949Seneca 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 Seneca.

People over time

Seneca, census by census

05001,0001,5002,0002,50018801900192019401960198020002020Peak: 2,336

Between 285 and 2,336 people in every census since 1870.

16 censuses, 1870–2020.

U.S. Census Bureau decennial counts, from the census table on Seneca’s Wikipedia page.

Famous people

2 famous people were born in Seneca

Writers, athletes, leaders and more, ranked by how widely they’re known.

See all →
Ronald L. WattsUnited States Army general · b. 1934
M
Morris WattsAmerican football coach · b. 1936

Questions about Seneca’s history

What year was Seneca founded?

The Seneca post office opened in 1869, the earliest record of the town by name (U.S. post office records).

How does Seneca rank for history?

Seneca is more historic than 45% 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 Seneca?

27% of Seneca’s homes were built before 1940 (Census estimate, ±7.5 points), against a typical 8.4% for a Missouri town; the median home was built in 1972.

Memory lane

What the archives can’t tell you, neighbors can.

Town Square →
Start a conversation
Sources

Where this page comes from

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 (10), 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.