Explore the Family Name O'Reilly

Possible origins of the surname O'Reilly

Your DNA provides clues about where your recent ancestors may have lived. Having many distant relatives in the same location suggests that you may all share common ancestry there. Locations with many distant relatives can also be places where people have migrated recently, such as large cities. If a large number of individuals who share your surname have distant relatives in a specific area, it could indicate a connection between your surname and that location, stemming from either recent ancestral ties or migration.

Based on 23andMe data, people with last name O'Reilly have recent ancestry locations in the United Kingdom of Great Britain and Northern Ireland and Ireland.

What O'Reilly haplogroups can tell you

Haplogroups are genetic population groups that share a common ancestor on either your paternal or maternal line. These paternal and maternal haplogroups shed light on your genetic ancestry and help tell the story of your family.

The top paternal haplogroup of people with the surname O'Reilly is R-A260, which is predominantly found among people with European ancestry. Haplogroup R-A260 is descended from haplogroup R-M343. Other common haplogroups include R-M222 and R-CTS241, which are predominantly found among people with European and European ancestry. Other surnames with similar common haplogroups are: Reilly, Geraghty, Fallon, O'Reilly, Mcdonough, Masterson, Mcgovern, Kiernan, Garrity, Tighe.

The most common maternal haplogroups of people with O'Reilly surname are: H1, H3, H. These most commonly trace back to individuals of European ancestry.

Your paternal lineage may be linked to Niall of the Nine Hostages

The spread of haplogroup R-M222 in northern Ireland and Scotland was likely aided by men like Niall of the Nine Hostages. Perhaps more myth than man, Niall is said to have been a King of Tara in northwestern Ireland in the late 4th century C.E. His name comes from a tale of nine hostages that he held from the regions he ruled over. Though the legendary stories of his life may have been invented hundreds of years after he died, genetic evidence suggests that the Uí Néill dynasty, whose name means "descendants of Niall," did in fact trace back to just one man who likely bore haplogroup R-M222, a branch of R-M269.The Uí Néill ruled to various degrees as kings of Ireland from the 7th to the 11th century C.E. In the highly patriarchal society of medieval Ireland, their status allowed them to have outsized numbers of children and spread their paternal lineage each generation. In fact, researchers have estimated that between 2 and 3 million men with roots in north-west Ireland are paternal-line descendants of Niall.

Your maternal lineage may be linked to Marie Antoinette

Because it is so dominant in the general European population, haplogroup H also appears quite frequently in the continent's royal houses. Marie Antoinette, an Austrian Hapsburg who married into the French royal family, inherited the haplogroup from her maternal ancestors. So did Prince Philip, Duke of Edinburgh, whose recorded genealogy traces his female line to Bavaria. Scientists also discovered that famed 16th century astronomer Nicolaus Copernicus traced his maternal lineages to haplogroup H.