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

O'Neil, 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 O'Neil surname is from the 2010 census data.

Popularity of O'Neil in America

O'Neil is the 1220th most popular name in America based on the data we have collected from the U.S. Census Bureau.

The O'Neil surname appeared 28,949 times in the 2010 census and if you were to sample 100,000 people in the United States, approximately 10 people would have the surname O'Neil.

We can also compare 2010 data for O'Neil 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 O'Neil

The surname ONEIL is of Irish origin, deriving from the Gaelic Ó Néill, meaning "descendant of Neill." It originated in the 5th century AD with the Cenél nEógain clan, one of the two main branches of the Northern Uí Néill dynasty that dominated parts of Ireland until the 17th century.

The name traces its roots to Niall Noígiallach (Niall of the Nine Hostages), a legendary High King of Ireland who ruled in the late 4th and early 5th centuries. He is said to have taken hostages from rival kingdoms, leading to his epithet "of the Nine Hostages."

The ONEIL surname first appeared in written records in the Annals of Ulster, a chronicle of medieval Irish history. In the year 1022, the death of Flaithbhertach Ua Néill, King of Ailech, is recorded.

One of the earliest known bearers of the name was Muircheartach Ua Néill (1050-1166), a King of Ailech and Cenél nEógain who fought against the Norman invasion of Ireland in the 12th century.

The name is also found in the Domesday Book of 1086, a survey of landholdings in England commissioned by William the Conqueror. This suggests that some ONEILs may have migrated to England in the aftermath of the Norman conquest of Ireland.

A notable figure in Irish history was Hugh O'Neill (1550-1616), Earl of Tyrone, who led the Irish rebellion against English rule in the Nine Years' War (1594-1603). He was ultimately forced into exile in Rome after his defeat.

Another prominent ONEIL was John O'Neill (1786-1838), a United Irishman and revolutionary who took part in the Irish Rebellion of 1798 against British rule. He later fled to the United States and became a prominent figure in the Irish American community.

Other notable individuals with the surname ONEIL include Eugene O'Neill (1888-1953), the American playwright and Nobel laureate known for works such as "Long Day's Journey Into Night" and "The Iceman Cometh," and Shaquille O'Neal (born 1972), the former NBA superstar and one of the most dominant players in basketball history.

Race and ethnic origin of people with the last name O'Neil

We also have some data on the ancestry of people with the surname O'Neil.

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 O'Neil 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 O'Neil 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 O'Neil was researched and written by our team of onomatology and genealogy experts.

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

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