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History · Diagonal

Diagonal’s post office opened in 1889, and 64% of its homes were built before 1940

Below: maps from 1981 on and the census since 1900.

1889first post office
0on the National Register
64%homes built before 1940
1famous people
Add an old photoShare a memory
Photo: Jared Winkler · CC BY-SA 4.0
Quick answers

How Diagonal began

When was Diagonal founded?

1889

The Diagonal post office opened in 1889, the earliest record of the town by name.

First census: 383 in 19002020 census: 344137 years
Founding year: the first Diagonal post office (Blevins & Helbock, CC0).

What stands out about Diagonal’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 Diagonal are in the public archives yet. The rest are in attics and albums.Old housesHalf of Diagonal’s homes were built before 1938.Boom and bustPeaked at 603 in 1940; 344 people lived here in 2020.
★ What stands out · Help out

Start Diagonal’s collection

The first neighbors to add old photos shape how Diagonal’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
The story so far

Diagonal, in brief

Wikipedia doesn’t have a history of Diagonal yet. The photos, dates and memories neighbors add here are how it gets written.

Diagonal is a city in northwest Ringgold County, Iowa, the United States. The population was 344 at the time of the 2020 census. The community was named for the fact that two railroads intersected diagonally near the town site.

Its first post office opened in 1889. Between the 2010 and 2020 censuses its population grew from 330 to 344 (+4%).

Intro from Wikipedia. Population: U.S. Census Bureau.

People over time

Diagonal, census by census

01002003004005006001900192019401960198020002020Peak: 603

Peaked at 603 in 1940; 344 people lived here in 2020.

13 censuses, 1900–2020.

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

Timeline

Diagonal, 1889 to 1981

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

  1. 19th century
  2. 1889Post officeThe Diagonal post office opens
  3. 20th century
  4. 1926Born hereDick Ives is born here
  5. 1940CensusPopulation peaks at 603
  6. 1981On the mapFirst mapped by the U.S. Geological Survey
By decade

Diagonal, decade by decade

Today3 recent
DiagonalIowaPopPlot2021DiagonalIowaPopPlotDiagonal, IA2019Diagonal, IAIAMap-doton-Diagonal2004IAMap-doton-Diagonal
On the map

Diagonal on the map in 1981

The U.S. Geological Survey’s map of Diagonal.

Diagonal on the 1981 USGS map1981Diagonal 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 Diagonal.

Places that used to be

Places now gone

Diagonal’s post office has been open since 1889.

Gone or out of use
Diagonallocale

US Post Offices dataset (Blevins & Helbock, CC0). Places and cemeteries from the USGS Geographic Names Information System (2021).

Questions about Diagonal’s history

What year was Diagonal founded?

The Diagonal post office opened in 1889, the earliest record of the town by name (U.S. post office records).

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). How TownRatings grades history →

From Wikimedia Commons (3), 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) 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.