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CHistory
History · Timonium

Timonium’s post office opened in 1833

More historic than 32% of U.S. towns · #137 of 261 in Maryland. What drives it

Most of Timonium was built recently: 2% of its homes predate 1940 and the median home dates from 1964. Below: maps from 1894 on and the census since 1960.

1833first post office
0on the National Register
2%homes built before 1940
Add an old photoShare a memory
Photo: Scott218 · CC BY-SA 3.0
Quick answers

How Timonium began

When was Timonium founded?

1833

The Timonium post office opened in 1833, the earliest record of the town by name. Another post office, Bosley (1886), opened inside today’s town and later closed.

First census: 12,265 in 19602020 census: 10,458193 years

How historic is Timonium?

C

More historic than 32% of U.S. towns, on its age, its old homes and the National Register.

What drives the grade ↓
Founding year: the first Timonium post office (Blevins & Helbock, CC0).
History grade

What drives Timonium’s History grade

On its age, its old homes and the National Register, Timonium is more historic than 32% of U.S. towns, #137 of 261 in Maryland. Its age holds the grade up; its share of homes from before 1940 pulls it down.

C
HistoryA character grade: shown, never part of Timonium’s overall grade.
Founding era1833, from the first post office: founded 1776–1849, an older era than 75% of U.S. townsA−Homes built before 19402.1% of homes (±1.6) · typical MD town 3.3% · U.S. 8.4%C−National RegisterNo listings counted · typical MD town 0.9 per 10,000 · U.S. 2.4C−
All U.S. towns we grade (21,289)Ahead of 32%
NewerOlder
Maryland towns of 2,500+ (261)Ahead of 48%

Few Maryland towns list much on the Register (a typical Maryland town has 0.9 per 10,000 residents, the U.S. 2.4), so Timonium’s 0.0 sits below most of its state (20% of Maryland towns have fewer) while its 0 listings outnumber those of 23% 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 (±1.6 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 Timonium’s past

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

A history waiting to be writtenNo old photos of Timonium are in the public archives yet. The rest are in attics and albums.Lost villages1 post office opened and closed inside today’s Timonium, and 12 old place names are still on the map.On the map since 18946 editions of the USGS map, 1894 to 1974. Watch Timonium change.Boom and bustPeaked at 24,055 in 1970; 10,458 people lived here in 2020.
★ What stands out · Help out

Start Timonium’s collection

The first neighbors to add old photos shape how Timonium’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
Places that used to be

Lost post offices and old corners

Timonium had its own post office from 1833 to 1957. Another post office, Bosley, opened and closed inside today’s town.

Timonium
1833–1957
Bosley
1886–1907
Lutherville-Timonium
1957–today
18301930today
Hamlets and corners on the map
BosleyHaverfordHunters HillNorthamptonPadoniaPot SpringSpringlakeStratfordTalbotts ChoiceTimonium HeightsValley CrestWakefield

US Post Offices dataset (Blevins & Helbock, CC0). Places and cemeteries from the USGS Geographic Names Information System (2021).

On the map

Timonium on the map, 1894 to 1974

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

Timonium on the 1894 USGS mapTimonium on the 1904 USGS mapTimonium on the 1944 USGS mapTimonium on the 1957 USGS mapTimonium on the 1966 USGS mapTimonium on the 1974 USGS map1894Baltimore 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 Timonium.

The story so far

Timonium, in brief

Wikipedia doesn’t have a history of Timonium yet. The photos, dates and memories neighbors add here are how it gets written.

Timonium is a census-designated place (CDP) in Baltimore County, Maryland, United States. As of the 2020 census, it has a population of 10,458. Prior to 2010 the area was part of the Lutherville-Timonium CDP. The Maryland State Fair is held in Timonium each year near Labor Day on the grounds of the former Timonium Race Course, which is an important site along with Pimlico Race Course in northwest Baltimore and Laurel Park in Prince George's County, along with other former tracks at Bowie and Rosecroft in Maryland thoroughbred horse racing traditions.

Its first post office opened in 1833. Between the 2010 and 2020 censuses its population grew from 9,925 to 10,458 (+5%).

Intro from Wikipedia. Population: U.S. Census Bureau.

Timeline

Timonium, 1833 to 1970

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

  1. 19th century
  2. 1833Post officeThe Timonium post office opens
  3. 1886Post officeThe Bosley post office opens
  4. 1894On the mapFirst mapped by the U.S. Geological Survey
  5. 20th century
  6. 1907Post officeThe Bosley post office closes
  7. 1957Post officeThe Timonium post office closes
  8. 1957Post officeThe Lutherville-Timonium post office opens
  9. 1970CensusPopulation peaks at 24,055
By decade

Timonium, decade by decade

Today12 recent
Timonium Testing Facility2020Timonium Testing FacilityTimonium Testing Facility2020Timonium Testing FacilityTimonium Testing Facility2020Timonium Testing FacilityTimonium Testing Facility2020Timonium Testing Facility2020-07-02 14 48 47 View north along Maryland State Route 45 (York Road) at East Ridgely Road in20202020-07-02 14 48 47 View north along Maryland State R…2019-06-21 11 29 28 View south along Interstate 83 (Baltimore-Harrisburg Expressway) at Exit 16 (Timonium Road) on the …20192019-06-21 11 29 28 View south along Interstate 83 (B…2019-06-21 10 09 49 View north along Interstate 83 (Baltimore-Harrisburg Expressway) at Exit 17 (Padonia Road) on the e…20192019-06-21 10 09 49 View north along Interstate 83 (B…2019-06-21 10 07 34 View north along Interstate 83 (Baltimore-Harrisburg Expressway) at Exit 16B (Timonium Road WEST, T…20192019-06-21 10 07 34 View north along Interstate 83 (B…2019-06-21 10 06 20 View north along Interstate 83 (Baltimore-Harrisburg Expressway) at Exit 16A (Timonium Road EAST, T…20192019-06-21 10 06 20 View north along Interstate 83 (B…Sam's Club2013Sam's ClubMarylandStateFair2013MarylandStateFairMDMap-doton-Lutherville-Timonium2004MDMap-doton-Lutherville-Timonium
People over time

Timonium, census by census

05,00010,00015,00020,00025,0001960198020002020Peak: 24,055

Peaked at 24,055 in 1970; 10,458 people lived here in 2020.

7 censuses, 1960–2020.

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

Stories next door

History across the town line

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

Cockeysville1 historic placeB−LuthervilleIts storyC−Hampton3 historic placesBMays Chapel1 historic placeB−

Questions about Timonium’s history

What year was Timonium founded?

The Timonium post office opened in 1833, the earliest record of the town by name (U.S. post office records).

How does Timonium rank for history?

Timonium is more historic than 32% of U.S. towns, #137 of 261 in Maryland. 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.

How old are the homes in Timonium?

2% of Timonium’s homes were built before 1940 (Census estimate, ±1.6 points), against a typical 3.3% for a Maryland town; the median home was built in 1964.

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), 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.