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History · Mercer

Mercer’s post office opened in 1818, and 14% of its homes were built before 1940

Its Register listings are the Ingalls House, the Mercer Union Meetinghouse and the Henry Knox Thatcher House. Below: maps from 1894 on and the census since 1810.

1818first post office
3on the National Register
14%homes built before 1940
3famous people
Add an old photoShare a memory
Quick answers

How Mercer began

When was Mercer founded?

1818

The Mercer post office opened in 1818, the earliest record of the town by name.

First census: 562 in 18102020 census: 709208 years
Founding year: the first Mercer post office (Blevins & Helbock, CC0).

What stands out about Mercer’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 Mercer are in the public archives yet. The rest are in attics and albums.Shrank, then grewLost two-thirds of its people between 1840 and 1960, then more than doubled.On the map since 18944 editions of the USGS map, 1894 to 1982. Watch Mercer change.Deep rootsA post office since 1818: 208 years of Mercer.
★ What stands out · Help out

Start Mercer’s collection

The first neighbors to add old photos shape how Mercer’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

Mercer, census by census

02004006008001,0001,2001,4001,60018501900195020001,432 in 1840Low: 272

Lost two-thirds of its people between 1840 and 1960, then more than doubled.

22 censuses, 1810–2020.

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

On the map

Mercer on the map, 1894 to 1982

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

Mercer on the 1894 USGS mapMercer on the 1943 USGS mapMercer on the 1956 USGS mapMercer on the 1982 USGS map1894Norridgewock 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 Mercer.

The story so far

Mercer, in brief

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

Mercer is a town in Somerset County, Maine, United States. The town was named after the Revolutionary War hero Hugh Mercer. The population was 709 at the 2020 census.

Its first post office opened in 1818. Between the 2010 and 2020 censuses its population grew from 664 to 709 (+7%).

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

Timeline

Mercer, 1808 to 1975

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

  1. 19th century
  2. 1808Born hereJames S. Wiley is born here
  3. 1818Post officeThe Mercer post office opens
  4. 1827Born hereJohn Gates is born here
  5. 1840CensusPopulation peaks at 1,432
  6. 1854Born hereFrank Munsey is born here
  7. 1894On the mapFirst mapped by the U.S. Geological Survey
  8. 20th century
  9. 1975Post officeThe Mercer post office closes
By decade

Mercer, decade by decade

Today7 recent
MercerME OldChurch2022MercerME OldChurchMercerME IngallsHouse2022MercerME IngallsHouseMercerME HistoricalSociety2022MercerME HistoricalSocietyMercerME GrangeHall2022MercerME GrangeHallMercer Union Meetinghouse2014Mercer Union MeetinghouseUS2wRoadsideSunsetTruck-MercerMaine2013US2wRoadsideSunsetTruck-MercerMaineSomersetCountyLine-MercerME2013SomersetCountyLine-MercerME
On the National Register

3 historic places in Mercer

The country’s official list of buildings and places worth saving.

places listed
3
National Historic Landmarks
0
none yet
historic buildings protected
3
each building in a district counts
first listed
1975
Ingalls House
Ingalls HouseMercer Union MeetinghouseHenry Knox Thatcher House
Buildings

Architectural styles listings

Greek Revival3
Early Republic2
Federal2
Mid-19th Century2
Gothic Revival1
Ingalls HouseGreek Revival
Mercer Union MeetinghouseEarly Republic
All 3 listings
Henry Knox Thatcher HouseBuilding · listed 2002

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

Famous people

3 famous people were born in Mercer

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

See all →
Frank MunseyAmerican publisher and politician · b. 1854
J
James S. WileyAmerican politician · b. 1808
John GatesMayor · b. 1827
Places that used to be

Lost post offices, old corners and burying grounds

Mercer had its own post office from 1818 to 1975.

Mercer
1818–1975
18101920today
Hamlets and corners on the map
East Mercer
5cemeteries and burying grounds inside Mercer
DickinsonElliot - YoungHampshire HillLadd - MercerMercer Village

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

Stories next door

History across the town line

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

Starks1 historic placenot graded: under 1,000 residents or part of its townSmithfield1 historic placenot graded: under 1,000 residents or part of its townNew Sharon2 historic placesA−Norridgewock7 historic placesA−RomeIts storyB−

Questions about Mercer’s history

What year was Mercer founded?

The Mercer post office opened in 1818, the earliest record of the town by name (U.S. post office records).

What is on the National Register in Mercer?

Three places: the Ingalls House (listed 1975), the Mercer Union Meetinghouse (2007) and the Henry Knox Thatcher House (2002).

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 (3), 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.