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

Reilly, 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 Reilly surname is from the 2010 census data.

Popularity of Reilly in America

Reilly is the 845th most popular name in America based on the data we have collected from the U.S. Census Bureau.

The Reilly surname appeared 40,884 times in the 2010 census and if you were to sample 100,000 people in the United States, approximately 14 people would have the surname Reilly.

We can also compare 2010 data for Reilly 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 Reilly

The surname Reilly originates from Ireland and is an anglicized version of the Gaelic name O'Raghailligh. It is believed to have derived from the Irish word riaghail, meaning "rule" or "regulator," suggesting that the name may have been initially bestowed upon a local official or magistrate.

In its early form, the name was often spelled as O'Reilly or O'Reyly. It is found in several ancient Irish manuscripts, such as the Annals of the Four Masters, which record notable individuals bearing the name as early as the 12th century.

One of the earliest recorded instances of the name Reilly can be found in the 14th-century Red Book of Ormond, which mentions a Richard Reilly as a witness to a land transaction in County Cavan, Ireland.

The Reilly family was particularly prominent in County Cavan, where they held significant lands and power. The name is also associated with several place names in the region, such as Killyreilly and Ballyreilly.

Notable individuals with the surname Reilly include:

1. Edmund Reilly (c. 1598-1669), a Roman Catholic Archbishop of Armagh who played a crucial role in the Irish Confederate Wars.
2. Andrew Reilly (1742-1809), an Irish-American merchant and politician who served as a delegate to the Continental Congress.
3. Winona Ryder (born Winona Laura Horowitz in 1971), an American actress whose stage name is derived from her father's surname, Reilly.
4. Philip Reilly (1788-1858), an Irish sculptor known for his works in Dublin, including the statue of Daniel O'Connell in the city center.
5. John Reilly (1786-1854), an Irish-American businessman and politician who served as the 16th Mayor of Philadelphia.

The surname Reilly has maintained a strong presence in Ireland, particularly in the counties of Cavan, Longford, and Westmeath, where it can trace its roots back to the medieval period.

Race and ethnic origin of people with the last name Reilly

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

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 Reilly 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 Reilly 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 Reilly was researched and written by our team of onomatology and genealogy experts.

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

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