Rialto’s post office opened in 1888, and 2 of its places are on the National Register
More historic than 34% of U.S. towns · #296 of 847 in California. What drives it
Its Register listings are the First Christian Church of Rialto and the San Antonio Heights Grove House. Most of Rialto was built recently: 2% of its homes predate 1940 and the median home dates from 1982. Below: 11 old photos and papers, maps from 1892 on, and the census since 1920.
Founding year: the first Rialto post office (Blevins & Helbock, CC0). Wikidata: 1911.The full story ↓
History grade
What drives Rialto’s History grade
On its age, its old homes and the National Register, Rialto is more historic than 34% of U.S. towns, #296 of 847 in California. 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 Rialto’s overall grade.
Among the 400 U.S. cities of 100,000 or more, Rialto ranks #291 on History.
Few California towns list much on the Register (a typical California town has 0.0 per 10,000 residents, the U.S. 2.4), so Rialto’s 0.3 sits above most of its state (67% of California towns have fewer) while its 3 historic buildings outnumber those of 65% of U.S. towns.
Newer cities are common at Rialto’s size: in the typical U.S. city of 100,000 or more, 5% of homes predate 1940.
How sure. Graded on any two of the three inputs instead, the letter would range from C− to B−. The pre-1940 share (±0.5 points) is firm at this size. The founding year is the first post office, not a stated founding date; Wikidata gives 1911.
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 Rialto’s past
Read from the archive, the National Register and the record. The page puts what stands out first.
Every edition of the U.S. Geological Survey’s map of Rialto. Tap a year, or press play to watch the town change.
1896San Bernardino sheet · 1:62,500
U.S. Geological Survey historical topographic maps (public domain), via Esri’s collection of the scans. The red ring marks the center of Rialto.
Every building
Rialto, building by building, 1892–1911
Fire insurance maps drew every building, what it was made of and what it was used for, so insurers could price the risk of fire. Pick a year, then a sheet.
Ancient artifacts discovered by archaeologists suggest that what is now the city of Rialto was settled prior to 1500. Such artifacts, now found at the Rialto Historical Society, indicate that the Serrano Indians lived in the Rialto area between 1500 and 1800 AD.
An adobe building from the early 19th century, which has been used for many purposes over the years, is the oldest building still standing in Rialto and stands restored near Bud Bender Park, formerly known as "Lilac Park" on Second Street and Riverside Avenue.
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.
The Rialto post office opened in 1888, the earliest record of the town by name (U.S. post office records). Wikidata gives 1911.
How does Rialto rank for history?
Rialto is more historic than 34% of U.S. towns, #296 of 847 in California. 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 Rialto?
Two places: the First Christian Church of Rialto (listed 2003) and the San Antonio Heights Grove House (2024).
How old are the homes in Rialto?
2% of Rialto’s homes were built before 1940 (Census estimate), against a typical 3.4% for a California town; the median home was built in 1982.
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 (18), the Library of Congress (1), the National Register of Historic Places (2), 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), the USGS Geographic Names Information System and Sanborn fire insurance maps (Library of Congress). Archive images are copied here with their credits and licenses, shown on each photo’s page. Refreshed monthly.
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