Hennessy
Derived from the Irish Ó hAonghusa, meaning "descendant of Aonghus," a personal name composed of Celtic elements meaning "one" and "choice."
According to the 2010 US Census Bureau surname tables, roughly 10,865 Americans carry the last name Hennessy. That puts it at #3,790 in the national surname ranking, appearing at a frequency of 3.17 per 100,000 people (about 1 in 31,547 residents).
This page is the full Name Census profile for the Hennessy surname. You will find the Census Bureau frequency data, an ancestry and ethnicity breakdown based on self-reported demographics, the name's meaning and origin where available, and answers to the most common questions people ask about this surname.
Bearers in the US
11K
1 in 31,547
Census rank
#3,790
2010 decennial data
Per 100,000
3.2
Frequency rate
Recorded bearers
9.3K
uncommon in the US
Popularity narrative
The Census Bureau recorded 9,338 bearers of the surname Hennessy in its 2010 decennial surname file. At a rate of 3.17 per 100,000 residents, it holds the 3790th position in the national surname ranking.
Among Census respondents with the surname Hennessy, the largest self-reported group is White at 94.7%. The next largest groups are Hispanic (2.1%) and Two or More Races (1.4%).
Origin
Meaning and origin of Hennessy
The surname Hennessy originated in Ireland. It is an Anglicized version of the Irish Gaelic name Ó hAonghusa, which means "descendant of Aonghus." The name Aonghus is derived from the old Irish word "oan," meaning "one," and the word "gus," meaning "choice" or "excellent."
The earliest recorded instances of the Hennessy surname date back to the 13th century in County Cork, Ireland. It is believed that the name originated in the Gaelic-speaking region of West Munster, particularly in the baronies of Muskerry and Duhallow.
In the Annals of the Kingdom of Ireland by the Four Masters, a historical chronicle written in the 17th century, there are several references to the Hennessy family and their involvement in various conflicts and battles during the medieval period.
One of the earliest known individuals with the surname Hennessy was Phillip Hennessy, who was born in County Cork around 1480. He was a prominent landowner and chieftain of the Hennessy clan in the region.
In the 16th century, the Hennessy family played a significant role in the Desmond Rebellions, which were a series of uprisings against English rule in Ireland. Sir John Hennessy (c. 1530-1598) was a notable figure during this period, leading the Hennessy clan in support of the rebel forces.
Another prominent individual from this era was Richard Hennessy (c. 1590-1650), who was a member of the Irish Parliament and a staunch supporter of Catholic rights during the Irish Confederate Wars.
During the 17th and 18th centuries, many members of the Hennessy family were forced to leave Ireland due to the Penal Laws and the suppression of Catholic landowners. Some settled in other parts of Europe, such as France, where they established the famous Hennessy cognac brand.
Notable individuals with the Hennessy surname include:
1. Richard Hennessy (1724-1800), the founder of the Hennessy cognac distillery in France.
2. John Pope Hennessy (1834-1891), an English writer and biographer.
3. James Hennessy (1837-1916), an Irish businessman and politician who served as a Member of Parliament.
4. Brendan Hennessy (1905-1959), an Irish playwright and novelist.
5. John Hennessy (born 1952), an American computer scientist and the 10th President of Stanford University.
Demographics
Ancestry and ethnicity for Hennessy
Among Census respondents with the surname Hennessy, the largest self-reported group is White at 94.7%. The next largest groups are Hispanic (2.1%) and Two or More Races (1.4%).
The bar chart below shows how Hennessy bearers described their own race and ethnicity on the 2010 Census form. The Census Bureau groups responses into six broad categories: White, Black or African American, Hispanic or Latino, Asian and Pacific Islander, American Indian and Alaska Native, and Two or More Races. When a category has too few respondents for a given surname, the Bureau suppresses the figure to protect individual privacy, which is why some names show fewer than six slices.
Keep in mind that these are self-reported numbers. A person's surname does not determine their race or ethnicity, and the distribution you see here reflects the specific population who happened to carry the Hennessy surname at the time of the 2010 Census, not any inherent property of the name itself.
- White94.7%
- Hispanic or Latino2.1%
- Two or more races1.4%
- Asian and Pacific Islander0.9%
- Black or African American0.6%
- American Indian and Alaska Native0.2%
Year on year
2000 vs 2010 Census
How has the Hennessy surname changed between Census years? The chart shows bearer count side by side, and the table compares rank, count, and frequency.
Census year comparison
| Metric | 2000 | 2010 | Change |
|---|---|---|---|
| Rank | #3,550 | #3,790 | -6.8% |
| Count | 9,187 | 9,338 | 1.6% |
| Per 100K | 3.41 | 3.17 | -7.0% |
Between the 2000 and 2010 Census, the number of Hennessy bearers went from 9,187 to 9,338 (+1.6% change). The surname moved down 240 positions in the national ranking, going from #3,550 to #3,790.
Notable bearers
Famous people with the surname Hennessy
FAQ
Hennessy surname: questions and answers
How common is the last name Hennessy?
The surname Hennessy holds position #3,790 in the US Census Bureau's surname ranking, with an estimated 10,865 living bearers. It occurs at a rate of 3.17 per 100,000 Americans.
What is the ethnic background of the Hennessy surname?
Among Census respondents with the surname Hennessy, the largest self-reported group is White at 94.7%. The next largest groups are Hispanic (2.1%) and Two or More Races (1.4%). These figures come from the 2010 Census Bureau surname tables, based on how respondents described their own race and ethnicity.
Where does this surname data come from?
All surname statistics on Name Census are drawn from the US Census Bureau's decennial surname frequency tables. These tables list every surname that appeared 100 or more times in the 2010 Census, along with a frequency rate and self-reported demographic breakdown. You can read the full explanation on our methodology page.