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History · Sinclair

Sinclair dates to 1868, and 38% of its homes were built before 1940

1 place in town is on the National Register, among them a historic district with 49 buildings. Below: 1 old photo or paper from 1954 on and the census since 1930.

1868founded
1on the National Register
38%homes built before 1940
1old photo or paper
Add an old photoShare a memory
Quick answers

How Sinclair began

When was Sinclair founded?

1868

Sinclair dates its founding to 1868 (Wikidata). The census first counted it in 1930.

First census: 727 in 19302020 census: 374158 years
Founding year: Wikidata. First post office: 1923.The full story ↓

What stands out about Sinclair’s past

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

A history waiting to be writtenOnly 1 old photo is in the public archives. The rest are in attics and albums.A historic districtThe Parco Historic District takes in 49 historic buildings.Old housesHalf of Sinclair’s homes were built before 1963.
★ What stands out · Help out

Start Sinclair’s collection

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

Decades since 1900 with photos
00s10s20s30s40s50s60s70s80s90s
1 of 10 decades. The empty ones are waiting for someone’s album.
Share a family photoSign in to add one+10
On the National Register

1 listing protects 49 historic buildings

The country’s official list of buildings and places worth saving.

place listed
1
National Historic Landmarks
0
none yet
historic buildings protected
49
each building in a district counts
first listed
1987
Parco Historic District
Parco Historic District
Districts

Architectural styles listings

Spanish Colonial1
Bungalow1
Parco Historic DistrictSpanish Colonial

National Park Service, National Register of Historic Places. Photos from Wikimedia Commons, credited on each place’s page.

The story

How Sinclair came to be

From Wikipedia’s history of Sinclair.

Read it all →

The town was originally called Parco, after the Producers & Refiners Corporation (or PARCO), which founded the refinery and the company town. It was renamed Sinclair after PARCO was acquired during the Great Depression by Sinclair Consolidated Oil Corporation. The original refinery, located just east of town, remains in use to this day. Sinclair's population was 433 at the 2010 census.

The town was built as a planned community in 1924–1925, designed by Denver architects Fisher & Fisher in a Spanish Colonial Revival style. The historic center of town was designated the Parco Historic District in 1987.

Text from Wikipedia, licensed CC BY-SA 4.0.

Timeline

Sinclair, 1868 to 1954

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

  1. 19th century
  2. 1868
    FoundingSinclair is established
  3. 20th century
  4. 1923Post officeThe Parco post office opens
  5. 1942Post officeThe Parco post office closes
  6. 1943Post officeThe Sinclair post office opens
  7. 1954In the archiveProject Blue Book report - 1954-03-6780980-CherokeeandSinclair-Wyoming
By decade

Sinclair, decade by decade

One decade in the archive so far: the 1950s. Scroll each row; tap a photo for its story.

1950s1 item
Project Blue Book report - 1954-03-6780980-CherokeeandSinclair-Wyoming1954Project Blue Book report - 1954-03-6780980-Cherokeean…Book
1960s–1990snothing yet
Nothing in the archives for these yearsWeddings on Main Street, storms, parades, school pictures, the old store. If it’s in your family album, it belongs here.
Add from your album
Today5 recent
MP 219 (Sinclair) 0462019MP 219 (Sinclair) 046MP 219 (Sinclair) 0452019MP 219 (Sinclair) 045Tank cars at Sinclair Refinery2011Tank cars at Sinclair RefinerySinclair refinery, Wyoming2008Sinclair refinery, WyomingParco Inn2008Parco Inn
People over time

Sinclair, census by census

020040060080019401960198020002020Peak: 775

Between 374 and 775 people in every census since 1930.

10 censuses, 1930–2020.

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

Famous people

Famous people close to Sinclair

Nobody well known was born in Sinclair itself, so here are the best known from just nearby.

See all →
Jesse GarciaAmerican actor · b. 1982
Joe HickeyAmerican politician · b. 1911
Clarence Addison Brimmer, Jr.United States District Judge · b. 1922
Howard Thomas OrvilleAmerican naval officer and meteorologist · b. 1901
Philip A. BrimmerUnited States federal judge · b. 1959
C. C. BeallAmerican illustrator · b. 1892
Places that used to be

Lost post offices

Sinclair’s post office has been open since 1943. Another post office, Parco, opened and closed inside today’s town.

Parco
1923–1942
Sinclair
1943–today
19201970today

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

Questions about Sinclair’s history

What year was Sinclair founded?

In 1868, according to Wikidata. Sinclair’s post office opened in 1923, and the census of 1930 counted 727 people here.

What is on the National Register in Sinclair?

One place: the Parco Historic District (listed 1987).

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 (6), the National Register of Historic Places (1), Wikipedia, 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.