Find out how popular the last name Hennessy is in the United States and learn more about the meaning, history, and race and ethnic origin of people in America who are named Hennessy.

Hennessy, like all of the last names we have data for, is identified by the U.S. Census Bureau as a surname which has more than 100 occurrences in the United States in the Decennial Census survey. The most recent statistics we have for the Hennessy surname is from the 2010 census data.

Popularity of Hennessy in America

Hennessy is the 3790th most popular name in America based on the data we have collected from the U.S. Census Bureau.

The Hennessy surname appeared 9,338 times in the 2010 census and if you were to sample 100,000 people in the United States, approximately 3 people would have the surname Hennessy.

We can also compare 2010 data for Hennessy to data from the previous census in 2000. The table below contains all of the statistics for both years in a side-by-side comparison.

The history of the last name 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.

Race and ethnic origin of people with the last name Hennessy

We also have some data on the ancestry of people with the surname Hennessy.

The below race categories are the modified race categories used in the Census Bureau's population estimates program. All people were categorized into six mutually exclusive racial and Hispanic origin groups:

1. White only
2. Black only
3. American Indian and Alaskan Native only
4. Asian and Pacific Islander only
5. Hispanic
6. Two or More Races

For the most recent 2010 census data, the race/ethnic origin breakdown for Hennessy was:

Note: Any fields showing (S) means the data was suppressed for privacy so that the data does not in any way identify any specific individuals.

Since we have data from the previous census in 2000, we can also compare the values to see how the popularity of Hennessy has changed in the 10 years between the two census surveys.

Data source

The last name data and ethnic breakdown of last names is sourced directly from the Decennial Census survey, conducted every 10 years by the United States Census Bureau.

The history and meaning of the name Hennessy was researched and written by our team of onomatology and genealogy experts.

If you have a correction or suggestion to improve the history of Hennessy, please contact us.

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