Dorchester’s post office opened in 1827, and 100% of its homes were built before 1940
How Dorchester began
When was Dorchester founded?
The Dorchester post office opened in 1827, the earliest record of the town by name.
History across the town line
Each neighbor’s History grade, on the same three inputs.
Questions about Dorchester’s history
What year was Dorchester founded?
The Dorchester post office opened in 1827, the earliest record of the town by name (U.S. post office records).
Memory lane
What the archives can’t tell you, neighbors can.
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 →