Densmore
An English-language surname whose exact origin is uncertain, though it is likely a later altered form of an older name beginning with Den-.
The #8,339 most common surname in the United States (2010 Census) — about 1 in every 77,750 Americans shares it.
Etymology
The historical evidence for Densmore is thin, and 19th-century surname writers seem to have treated it mainly as a name to be compared with other Den- forms rather than as a clearly explained headword. A plausible explanation is that it is a later spelling or reduced form of an older surname beginning with Den- and ending in -more, but the exact source element is not secure. Because of that, the safest reading is that the name’s literal meaning is unclear rather than firmly established.
History
In the sources provided, Densmore is mentioned only in passing among lists of surnames, which suggests it was recognized as a real but not especially common name. In the United States it is uncommon today, with a few thousand bearers at most. The surname is likely to have been stabilized in English-speaking North America in the 18th or 19th century, but the excerpted sources do not give a firm origin story.
Origin
Regions
Variant spellings
Fun fact
Because older surname books often grouped similar-looking names together, Densmore is the kind of surname that can appear in historical indexes without a single agreed-upon derivation.
From the historical record
“Dermodv. Densmore. Donnallon. MDougall.”
— Varieties and Synonymes of Surnames and Christian Names in Ireland