Guest, Sign inJoin

Post to Rocky Hill

We’ll email a one-tap link to publish your post. No password, and nothing is public until you click it.
Already a member? Sign in
91 Washington Street, Rocky Hill, NJ - historic Dutch Reformed ChurchPhoto: Zeete · CC BY-SA 4.0
–Not graded
History · Rocky Hill

Rocky Hill’s post office opened in 1828, and 33% of its homes were built before 1940

1 place in town is on the National Register, among them a historic district with 133 buildings. Below: 1 old photo or paper, maps from 1888 on, and the census since 1900.

1828first post office
1on the National Register
33%homes built before 1940
1old photo or paper
2famous people
Add an old photoShare a memory
Quick answers

How Rocky Hill began

When was Rocky Hill founded?

1828

The Rocky Hill post office opened in 1828, the earliest record of the town by name. Wikidata gives 1889.

First census: 354 in 19002020 census: 743198 years
Founding year: the first Rocky Hill post office (Blevins & Helbock, CC0). Wikidata: 1889.The full story ↓

What stands out about Rocky Hill’s past

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

A historic districtThe Rocky Hill Historic District takes in 133 historic buildings.A history waiting to be writtenOnly 1 old photo is in the public archives. The rest are in attics and albums.Shrank, then grewLost a third of its people between 1910 and 1920, then more than doubled.On the map since 18887 editions of the USGS map, 1888 to 1995. Watch Rocky Hill change.
★ What stands out · On the National Register

1 listing protects 133 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
133
each building in a district counts
first listed
1982
Rocky Hill Historic District
Rocky Hill Historic District
Districts
Rocky Hill Historic DistrictDistrict

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

Help out

Start Rocky Hill’s collection

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

Decades since 1900 with photos
00s10s20s30s40s50s60s70s80s90s
0 of 10 decades. The empty ones are waiting for someone’s album.
Share a family photoSign in to add one+10
People over time

Rocky Hill, census by census

02004006008001,0001900192019401960198020002020502 in 1910Low: 305

Lost a third of its people between 1910 and 1920, then more than doubled.

13 censuses, 1900–2020.

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

The story

How Rocky Hill came to be

From Wikipedia’s history of Rocky Hill.

Read it all →

The earliest European settlement in the area began after John Harrison negotiated the purchase of land in 1701 from the Lenape Native Americans. Speaking an Algonquian language, they had occupied the area for centuries prior to the arrival of European settlers. Bands of Lenape lived along the coast from Connecticut through New York and New Jersey and south to Maryland and Delaware.

Text from Wikipedia, licensed CC BY-SA 4.0.

Timeline

Rocky Hill, 1781 to 1996

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

  1. 18th century
  2. 1781Born hereJohn M. Berrien is born here
  3. 19th century
  4. 1828Post officeThe Rocky Hill post office opens
  5. 1850In the archiveMap of Somerset County, New Jersey - Rocky Hill detail, 1850
  6. 1888On the mapFirst mapped by the U.S. Geological Survey
  7. 20th century
  8. 1970CensusPopulation peaks at 917
  9. 1996Born hereAnthony Cassar is born here
By decade

Rocky Hill, decade by decade

One decade in the archive so far: the 1850s. Scroll each row; tap a photo for its story.

1850s1 item
Map of Somerset County, New Jersey - Rocky Hill detail, 18501850Map of Somerset County, New Jersey - Rocky Hill detai…Map
Today6 recent
Workmen at the Atlantic Terracotta works in2015Workmen at the Atlantic Terracotta works inRocky Hill-Griggstown footbridge2015Rocky Hill-Griggstown footbridgePennsylvania Railroad depot in Rocky Hill, New Jersey (1922)2015Pennsylvania Railroad depot in Rocky Hill, New Jersey…Time in the woods2009Time in the woodsRocky hill nj 0352005Rocky hill nj 035Millstone River2004Millstone River
On the map

Rocky Hill on the map, 1888 to 1995

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

Rocky Hill on the 1888 USGS mapRocky Hill on the 1894 USGS mapRocky Hill on the 1906 USGS mapRocky Hill on the 1943 USGS mapRocky Hill on the 1954 USGS mapRocky Hill on the 1970 USGS mapRocky Hill on the 1995 USGS map1888Princeton 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 Rocky Hill.

Famous people

2 famous people were born in Rocky Hill

Writers, athletes, leaders and more, ranked by how widely they’re known.

See all →
John M. BerrienAmerican politician from Georgia, United States · b. 1781
A
Anthony CassarAmerican wrestler · b. 1996
Stories next door

History across the town line

Each neighbor’s History grade, on the same three inputs.

Montgomery Township9 historic placesB+Franklin Township10 historic placesBEast Rocky Hill2 historic placesnot graded: under 1,000 residents or part of its townKingston3 historic placesnot graded: under 1,000 residents or part of its town

Questions about Rocky Hill’s history

What year was Rocky Hill founded?

The Rocky Hill post office opened in 1828, the earliest record of the town by name (U.S. post office records). Wikidata gives 1889.

What is on the National Register in Rocky Hill?

One place: the Rocky Hill Historic District (listed 1982).

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 (7), the National Register of Historic Places (1), 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) 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.