An Irish and Scottish surname, O’Neil comes from the Gaelic terms ‘ua’ and ‘neill’ which refer to the grandson of Niall. The term ‘niall’ means a passionate person, a champion. The spelling variations for O’Neil include O’Neill, O’Neall, and O’Neal with the O’Neill spelling the most common and the O’Neil spelling rare. In northern England is where the majority with the O’Neil surname have lived over the years. The higher populations are in Lanarkshire, Cheshire, Yorkshire and Warwickshire. In Scotland most of the O’Neil families lived all across the country. The larger population are concentrated in Lanarkshire and Renfrewshire. Within the United States the original O’Neil families settled in Massachusetts, New York, Pennsylvania, Ohio, New Jersey, Illinois and Missouri. Famous: Amber O’Neil (professional wrestler), Deltha O’Neil (professional football player), Dennis O’Neil (major comic book writer), John O’Neil (FBI terrorist expert), Arthur O’Neil (accomplished 18th century harpist), John O’Neil (artist), Jack O’Neil (top world surfer) and Buck O’Neil (baseball player and head of the Negro Leagues Baseball Museum in Kansas).