View the most religious surnames in Ireland

Where Does The Last Name O'Nil Come From? ^{nationality or country of origin}

O'Nil is carried by more people in The United States than any other country/territory. It can also occur in the variant forms:. Click here to see other possible spellings of this last name.

How Common Is The Last Name O'Nil? ^{popularity and diffusion}

The surname is the 7,593,402^nd most frequent family name world-wide. It is borne by approximately 1 in 1,214,590,986 people. O'Nil is predominantly found in The Americas, where 67 percent of O'Nil are found; 50 percent are found in North America and 33 percent are found in Anglo-North America. It is also the 4,548,448^th most commonly occurring first name in the world, borne by 7 people.

O'Nil is most frequent in The United States, where it is held by 2 people, or 1 in 181,229,466. In The United States it is mostly concentrated in: Delaware, where 50 percent live and Missouri, where 50 percent live. Excluding The United States this last name exists in 5 countries. It is also found in Brazil, where 17 percent live and Canada, where 17 percent live.

O'Nil Family Population Trend ^{historical fluctuation}

The frequency of O'Nil has changed through the years. In The United States the share of the population with the last name contracted 60 percent between 1880 and 2014.

O'Nil Last Name Statistics ^demography

The religious adherence of those bearing the last name is chiefly Catholic (100%) in Ireland.