Find out how popular the last name O'Neill 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'Neill.

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

Popularity of O'Neill in America

O'Neill is the 689th most popular name in America based on the data we have collected from the U.S. Census Bureau.

The O'Neill surname appeared 50,028 times in the 2010 census and if you were to sample 100,000 people in the United States, approximately 17 people would have the surname O'Neill.

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

The surname O'Neill is of Irish origin, derived from the Gaelic "Ua Néill" meaning "descendant of Niall." It traces its roots back to the ancient kingdom of Ailech in the northern parts of Ireland, particularly in modern-day County Tyrone and County Londonderry.

The surname has its origins in the 4th century AD when Niall Noígiallach, also known as Niall of the Nine Hostages, was a prominent and powerful High King of Ireland. He established the Uí Néill dynasty, which ruled various parts of Ireland for centuries.

One of the earliest recorded references to the name can be found in the Annals of Ulster, a chronicle of medieval Irish history. The annals mention several members of the Uí Néill dynasty, including Áed Oirdnide mac Néill, who died in 819 AD.

Another notable early reference is the Book of Armagh, a 9th-century manuscript containing some of the oldest surviving examples of Old Irish writing. It mentions several individuals with the surname, such as Fergus O'Neill, who was the abbot of Armagh in the 8th century.

During the Middle Ages, the O'Neills were one of the most powerful and influential families in Ireland. They ruled the Kingdom of Ailech and later the Principality of Tír Eógain (Tyrone). Some notable individuals include Niall Glúndub (d. 919), a powerful king of Ailech, and Muircheartach O'Neill (d. 1166), who was the King of Ailech and Tír Eógain.

In the 16th century, the O'Neills played a significant role in the Tudor conquest of Ireland. Hugh O'Neill, Earl of Tyrone (c. 1550–1616), led a major rebellion against English rule, which became known as the Nine Years' War (1594–1603). Despite initial successes, the rebellion was eventually defeated.

Other notable individuals with the surname include Sir Phelim O'Neill (c. 1604–1653), who led the Irish Rebellion of 1641, and John O'Neill (1834–1904), an Irish-American artist and sculptor who designed several famous monuments in New York City.

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

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

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'Neill 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'Neill 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'Neill 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'Neill, please contact us.

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