The Riverdale post office opened in 1889, the earliest record of the town by name. Wikidata gives 1923. Another post office, Pompton (1814), opened inside today’s town and later closed.
First census: 1,052 in 19302020 census: 4,107137 years
How historic is Riverdale?
B−
More historic than 45% of U.S. towns, on its age, its old homes and the National Register.
Founding year: the first Riverdale post office (Blevins & Helbock, CC0). Wikidata: 1923.
History grade
What drives Riverdale’s History grade
On its age, its old homes and the National Register, Riverdale is more historic than 45% of U.S. towns, #335 of 468 in New Jersey. Its share of homes from before 1940 holds the grade up; its age pulls it down.
B−
HistoryA character grade: shown, never part of Riverdale’s overall grade.
New Jersey towns list more on the Register than most of the country (a typical New Jersey town has 3.7 per 10,000 residents, the U.S. 2.4), so Riverdale’s 2.4 sits near the middle of its state (42% of New Jersey towns have fewer) while its 1 listings outnumber those of 51% of U.S. towns.
How sure. Graded on any two of the three inputs instead, the letter would range from C to B−. The pre-1940 share is a Census survey estimate (±4.7 points). The founding year is the first post office, not a stated founding date; Wikidata gives 1923.
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 Riverdale’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 Riverdale. Tap a year, or press play to watch the town change.
1888Morristown 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 Riverdale.
The story so far
Riverdale, in brief
Wikipedia doesn’t have a history of Riverdale yet. The photos, dates and memories neighbors add here are how it gets written.
Riverdale is a borough in Morris County, in the U.S. state of New Jersey. As of the 2020 United States census, the borough's population was 4,107, an increase of 548 (+15.4%) from the 2010 census count of 3,559, which in turn reflected an increase of 1,061 (+42.5%) from the 2,498 counted in the 2000 census. Riverdale was incorporated as a borough by an act of the New Jersey Legislature on March 12, 1923, from portions of Pequannock Township, subject to the results of a referendum passed on April 17, 1923. Riverdale is situated in the northeasternmost part of Morris County bordering Passaic County along the Pequannock and Pompton rivers.
Its first post office opened in 1889. Between the 2010 and 2020 censuses its population grew from 3,559 to 4,107 (+15%).
Intro from Wikipedia. Population: U.S. Census Bureau.
From the old history books
What they wrote about Riverdale in 1914
Passages that mention Riverdale, cut from the printed page as they were published.
A history of Morris County, New Jersey1914 · page 148Read the page →
Read the text
general course of the Passaic river entering and leaving the township twice, but within the township the greater part of the distance along the eastern and northern border. The important stations on the line are the borough of Butler, the principal town of the township ; Pompton Plains and Riverdale. Pequannock was one of the three original townships into which Morris county was divided, and in general terms included all that part from the Pequannock river on the north to Lake Hopatcong on the west, and the Rockaway river on the south. The first township officers were appointed by
Text read by machine from the scan; it may contain errors.
A history of Morris County, New Jersey1914 · page 151Read the page →
Read the text
the road leading to Boonton. The next was a frame building erected in 1785 ; a third in 1816, and a fourth in 1852. Other school houses have been erected from time to time, the present system including schools at Brook Valley, Jacksonville, Lincoln Park, Pompton Plains, Riverdale and Meadtown. For the school year ending June, 1913, the township expended for its public schools, $14,826.96. The total enrollment of scholars was 437, the average daily attendance 300. For the years 1913-14 eleven teachers were
Text read by machine from the scan; it may contain errors.
Scans and text from the Internet Archive. Books published in 1930 or earlier, which are in the public domain.
Timeline
Riverdale, 1814 to 1974
Woven from the archive, old maps, post office records, the National Register and the people born here.
The Riverdale post office opened in 1889, the earliest record of the town by name (U.S. post office records). Wikidata gives 1923.
How does Riverdale rank for history?
Riverdale is more historic than 45% of U.S. towns, #335 of 468 in New Jersey. 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 Riverdale?
One place: the Slater's Mill (listed 1975).
How old are the homes in Riverdale?
14% of Riverdale’s homes were built before 1940 (Census estimate, ±4.7 points), against a typical 15% for a New Jersey town; the median home was built in 1996.
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 (6), Wikidata (1), the National Register of Historic Places (1), 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 old county and town histories (Internet Archive). Archive images are copied here with their credits and licenses, shown on each photo’s page. Refreshed monthly.
Date?
2025
2024
2007
2007
2007