Each edition grades its towns against each other only.
More historic than 14% of U.S. towns. What drives it
Most of San Ysidro was built recently: 3% of its homes predate 1940 and the median home dates from 1991. Below: 2 old photos and papers and maps from 1941 on.
More historic than 14% of U.S. towns, on its age, its old homes and the National Register.
On its age, its old homes and the National Register, San Ysidro is more historic than 14% of U.S. towns. Its National Register listings hold the grade up; its share of homes from before 1940 pulls it down.
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 San Ysidro’s 0.0 sits below most of its state (28% of New Mexico towns have fewer) while its 0 listings outnumber those of 23% of U.S. towns.
Founding year: our sources. 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 →
Read from the archive, the National Register and the record. The page puts what stands out first.
The first neighbors to add old photos shape how San Ysidro’s history is told.
Wikipedia doesn’t have a history of San Ysidro yet. The photos, dates and memories neighbors add here are how it gets written.
San Ysidro is a census-designated place in Doña Ana County, New Mexico. Its population was 2,090 as of the 2010 census.
Between the 2010 and 2020 censuses its population grew from 2,090 to 2,133 (+2%).
Intro from Wikipedia. Population: U.S. Census Bureau.
One decade in the archive so far: the 1940s. Scroll each row; tap a photo for its story.
Every edition of the U.S. Geological Survey’s map of San Ysidro. Tap a year, or press play to watch the town change.
U.S. Geological Survey historical topographic maps (public domain), via Esri’s collection of the scans. The red ring marks the center of San Ysidro.
No then-and-now pairs yet. Take a photo from the same spot as an old one and they appear here side by side.
Find the spot, match the angle, and add your photo. It becomes the first then-and-now pair on San Ysidro’s page.
Retake this view · +15Nobody well known was born in San Ysidro itself, so here are the best known from just nearby.
San Ysidro is more historic than 14% 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.
3% of San Ysidro’s homes were built before 1940 (Census estimate, ±3.6 points), against a typical 2.3% for a New Mexico town; the median home was built in 1991.
What the archives can’t tell you, neighbors can.
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 the Library of Congress (2), U.S. Geological Survey historical maps 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.
1940
1940
