Irish ancestry is a term that refers to a person's ancestral ties to the country of Ireland. Many people around the world can trace their roots back to Ireland, and Irish ancestry is particularly common in countries such as the United States, Canada, Australia, and the United Kingdom, which have large Irish diaspora populations.

Ireland has a rich and complex history of migration, with waves of people coming to and leaving the country over the centuries. The earliest known settlers in Ireland were the Celts, who arrived on the island around 500 BCE. In the centuries that followed, Ireland was invaded and settled by a variety of different peoples, including Vikings and Normans.

Irish emigration has been a significant feature of the country's history, with many people leaving Ireland to seek opportunities abroad. During the 19th century, millions of Irish people emigrated to countries such as the United States and Canada, and today, the Irish diaspora is estimated to number in the tens of millions worldwide.

Many people with Irish ancestry feel a strong connection to Ireland and its culture, and they may celebrate Irish holidays and traditions, such as St. Patrick's Day or traditional Irish music and dance. Genealogy and tracing family roots is also a popular pastime among those with Irish ancestry, as many people seek to connect with their heritage and learn more about their family history.