# Fennessy (surname)

Source: https://namelineage.com/surname/fennessy/  
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 | patronymic, formed from a father’s (or ancestor’s) given name |
| People in the US (2010 Census) | 932 |
| US rank (2010) | 26,229 of 162,253 |
| How often | about 1 in every 331,272 people |
| Change since 2000 | +22% (762 in 2000) |
| Pronunciation | not recorded |
| Variant spellings | Fennessey |

## Etymology

Reduced Anglicized form of Irish Ó Fionnghusa (“descendant of Fionnghus”), a personal name based on fionn (“fair, white”) + gus (“vigor, force”).

## Who carries it

Share of people named Fennessy 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) | 94% |
| Hispanic or Latino (any race) | 4.0% |
| Asian and Pacific Islander | 0.5% |
| Two or more races | 1.2% |

## Similar surnames

Fenske, Finch, Fink, Funk, Fong, Feng, Fang, Fung, Funes, Fenwick, Finke, Funke.

## 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.