Sullivan is a surname of Irish origin. An approximate 78 percent of Sullivans are located in the United States as it is the 105th most common surname according to the 2010 US census. [1] [2]
The name is an anglicised form of O'Sullivan (Ó Súilleabháin). Due to immigration out of Ireland, is most common in North America, and also found in Australia, as well as Britain.