# Grennan (surname)

Source: https://namelineage.com/surname/grennan/  
Publisher: Name Lineage. Counts from the US Census Bureau; origin and etymology from Wiktionary; bearers from Wikidata. Data updated 2026-11-11.

A surname from Irish.

| Field | Value |
|---|---|
| Origin | Irish |
| Type | not recorded |
| People in the US (2010 Census) | 854 |
| US rank (2010) | 28,049 of 162,253 |
| How often | about 1 in every 361,529 people |
| Change since 2000 | -4.6% (895 in 2000) |
| Pronunciation | not recorded |
| Variant spellings | none recorded |

## Etymology

* As an English surname of Norman origin, from Old French grenon (“mustache”), from Vulgar Latin *granonem (“facial hair, mustache”), from Frankish *granu, from Proto-Germanic *granō (“awn, beard-hair, hair-tips, mustache”). * As an Irish surname, variant of Greenan.

## Who carries it

Share of people named Grennan in the 2010 US Census by the Census's own race and ethnicity groups. The Census suppresses a share when the count behind it is small.

| Group | Share |
|---|---|
| White (not Hispanic) | 96% |
| Black (not Hispanic) | 0.9% |
| Asian and Pacific Islander | 1.2% |
| Two or more races | 1.5% |

## Similar surnames

Greenan, Greenman, Greening, Gorman, German, Garman, Germain, Garmon, Germany, Geronimo, Germann, Germano.

## How to read these numbers

A Census count is people alive and counted in 2010, not births, and names occurring fewer than 100 times are not published at all. Ethnicity shares are the Census's own categories.