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C−History
History · Los Alamos

Los Alamos’ post office opened in 1941, and 5 of its places are on the National Register

More historic than 21% of U.S. towns · #42 of 73 in New Mexico. What drives it

Most of Los Alamos was built recently: 0.0% of its homes predate 1940 and the median home dates from 1975. 5 places in town are on the National Register, among them the Los Alamos Scientific Laboratory, a National Historic Landmark, and a historic district with 17 buildings. Below: 2 old photos and papers, maps from 1952 on, and the census since 1970.

1941first post office
5on the National Register
0.0%homes built before 1940
2old photos & papers
Add an old photoShare a memory
From Los Alamos’ archive · credits on each photo
Quick answers

How Los Alamos began

When was Los Alamos founded?

1941

The Los Alamos post office opened in 1941, the earliest record of the town by name.

First census: 11,310 in 19702020 census: 13,17985 years

How historic is Los Alamos?

C−

More historic than 21% of U.S. towns, on its age, its old homes and the National Register.

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

What drives Los Alamos’ History grade

On its age, its old homes and the National Register, Los Alamos is more historic than 21% of U.S. towns, #42 of 73 in New Mexico. Its National Register listings hold the grade up; its share of homes from before 1940 pulls it down.

C−
HistoryA character grade: shown, never part of Los Alamos’ overall grade.
Founding era1941, from the first post office: founded 1900–1944, an older era than 9% of U.S. townsDHomes built before 19400.0% of homes (±0.3) · typical NM town 2.3% · U.S. 8.4%D−National Register5 listings, 18 historic buildings, 13.5 per 10,000 residents · typical NM town 2.2 · U.S. 2.4A−
All U.S. towns we grade (21,289)Ahead of 21%
NewerOlder
New Mexico towns of 2,500+ (73)Ahead of 43%

New Mexico towns list about as much on the Register as the country (a typical New Mexico town has 2.2 per 10,000 residents, the U.S. 2.4), so Los Alamos’ 13.5 sits above most of its state (76% of New Mexico towns have fewer) while its 18 historic buildings outnumber those of 79% of U.S. towns.

How sure. Graded on any two of the three inputs instead, the letter would range from D− to C+. The pre-1940 share (±0.3 points) is firm at this size. 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 Los Alamos’ past

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

A history waiting to be writtenOnly 2 old photos are in the public archives. The rest are in attics and albums.A National Historic Landmark5 places on the National Register, including Los Alamos Scientific Laboratory, a National Historic Landmark.
★ What stands out · Help out

Start Los Alamos’s collection

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

Decades since 1900 with photos
00s10s20s30s40s50s60s70s80s90s
1 of 10 decades. The empty ones are waiting for someone’s album.
Retake an old viewSkiing Group at Los Alamos candid: stand where they stood+15Share a family photoSign in to add one+10
On the National Register

5 listings protect 18 historic buildings

The country’s official list of buildings and places worth saving. One is a National Historic Landmark, the highest tier.

places listed
5
National Historic Landmark
1
Los Alamos Scientific Laboratory
historic buildings protected
18
each building in a district counts
first listed
1966
Los Alamos Scientific Laboratory
Bayo Road, built 1943Grant RoadUnited States Post Office-Los Alamos, New MexicoLujan RoadLos Alamos Scientific Laboratory, built 1943★
BuildingsDistrictsStructures★ landmark

Architectural styles listings

Road3
Bayo RoadRoad · Built 1943
Grant RoadRoad
United States Post Office-Los Alamos, New MexicoBuilding
All 5 listings
Los Alamos Scientific LaboratoryDistrict · listed 1966Lujan RoadStructure · listed 2005

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

The story

How Los Alamos came to be

From Wikipedia’s history of Los Alamos.

Read it all →

The ruins of Puebloan settlements, such as those in nearby Bandelier National Monument and Tsankawi, and numerous other sites such as cliff dwellings indicate that the area has been inhabited during various eras since around 1150 AD. The first settlers on the plateau are thought to be Keres-speaking Native Americans around the 10th century. Around 1300, Tewa settlers immigrated from the Four Corners Region and built large cities but were driven out within 50 years by Navajo and Apache raids and by drought.

Text from Wikipedia, licensed CC BY-SA 4.0.

Timeline

Los Alamos, 1941 to 1965

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

  1. 20th century
  2. 1941Post officeThe Los Alamos post office opens
  3. 1943BuiltLos Alamos Scientific Laboratory is built
  4. 1943BuiltBayo Road is built
  5. 1943In the archiveSkiing Group at Los Alamos candid
  6. 1952On the mapFirst mapped by the U.S. Geological Survey
  7. 1965LandmarkLos Alamos Scientific Laboratory named a National Historic Landmark
By decade

Los Alamos, decade by decade

One decade in the archive so far: the 1940s. Scroll each row; tap a photo for its story.

1940s2 items
Skiing Group at Los Alamos candid1943Skiing Group at Los Alamos candidSkiing Group at1943Skiing Group at
1950s–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
Today10 recent
Los Alamos2012Los AlamosView from Window - Las Conchas Fire2011View from Window - Las Conchas FireNew growth2009New growthLos Alamos ramp2008Los Alamos rampLos Alamos Aerial2006Los Alamos AerialLos-alamos2005Los-alamosNMMap-doton-LosAlamos2004NMMap-doton-LosAlamosDebris catcher2002Debris catcherOttowiView2001OttowiViewFEMA - 1424 - Photograph by Andrea Booher taken on 04-19-2001 in New Mexico2001FEMA - 1424 - Photograph by Andrea Booher taken on 04…
On the map

Los Alamos on the map, 1952 to 2002

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

Los Alamos on the 1952 USGS mapLos Alamos on the 1984 USGS mapLos Alamos on the 1993 USGS mapLos Alamos on the 2002 USGS map1952Guaje Mountain 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 Los Alamos.

Then & now

Stand where they stood

No then-and-now pairs yet. Take a photo from the same spot as an old one and they appear here side by side.

Skiing Group at Los Alamos candid
Retake this viewSkiing Group at Los Alamos candid, 1943

Find the spot, match the angle, and add your photo. It becomes the first then-and-now pair on Los Alamos’ page.

Retake this view · +15
People over time

Los Alamos, census by census

02,0004,0006,0008,00010,00012,00014,000198020002020Peak: 13,179

Between 11,039 and 13,179 people in every census since 1970.

6 censuses, 1970–2020.

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

Questions about Los Alamos’ history

What year was Los Alamos founded?

The Los Alamos post office opened in 1941, the earliest record of the town by name (U.S. post office records).

How does Los Alamos rank for history?

Los Alamos is more historic than 21% of U.S. towns, #42 of 73 in New Mexico. 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.

What is on the National Register in Los Alamos?

5 listings: 1 building, 1 historic district, the Los Alamos Scientific Laboratory, with 17 contributing buildings, and 3 structures. 18 historic buildings in all.

How old are the homes in Los Alamos?

0.0% of Los Alamos’ homes were built before 1940 (Census estimate), against a typical 2.3% for a New Mexico town; the median home was built in 1975.

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 (12), the National Register of Historic Places (5), Wikipedia, 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.