Guest, Sign inJoin

Post to Sinai

We’ll email a one-tap link to publish your post. No password, and nothing is public until you click it.
Already a member? Sign in
–Not graded
History · Sinai

Sinai’s post office opened in 1891, and 57% of its homes were built before 1940

Below: maps from 1968 on and the census since 1920.

1891first post office
0on the National Register
57%homes built before 1940
1famous people
Add an old photoShare a memory
Quick answers

How Sinai began

When was Sinai founded?

1891

The Sinai post office opened in 1891, the earliest record of the town by name.

First census: 216 in 19202020 census: 99135 years
Founding year: the first Sinai post office (Blevins & Helbock, CC0).The full story ↓

What stands out about Sinai’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 Sinai are in the public archives yet. The rest are in attics and albums.Old housesHalf of Sinai’s homes were built before 1938.
★ What stands out · Help out

Start Sinai’s collection

The first neighbors to add old photos shape how Sinai’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

How Sinai came to be

From Wikipedia’s history of Sinai.

Read it all →

Sinai was laid out in 1907, and named after the Biblical Mount Sinai.

Text from Wikipedia, licensed CC BY-SA 4.0.

Timeline

Sinai, 1891 to 1970

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

  1. 19th century
  2. 1891Post officeThe Sinai post office opens
  3. 20th century
  4. 1968On the mapFirst mapped by the U.S. Geological Survey
  5. 1970Born hereLauren Nelson is born here
By decade

Sinai, decade by decade

Today1 recent
SDMap-doton-Sinai2004SDMap-doton-Sinai
On the map

Sinai on the map, 1968 to 1985

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

Sinai on the 1968 USGS mapSinai on the 1985 USGS map1968Sinai 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 Sinai.

People over time

Sinai, census by census

0100200192019401960198020002020Peak: 217

Between 99 and 217 people in every census since 1920.

11 censuses, 1920–2020.

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

Questions about Sinai’s history

What year was Sinai founded?

The Sinai post office opened in 1891, 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 (1), 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) 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.