List of Irish clans

The following is a list of Irish clans sourced from modern published sources.
Unlike Scottish clans which are defined by surnames recognized by Scottish law of the Court of the Lord Lyon, there is no definitive authority on which surnames are regarded as Irish clans.
Clans of Ireland is a modern organization that was started in 1989 and has eligibility criteria for surnames to be included on their register of Irish clans. This includes that the family or clan can trace their ancestry back to before 1691 which is generally considered to mark the end of the clan based lineage system in Ireland. There can be more than one clan with the same surname if of a different ancestry. Clans of Ireland lists the following clans on their Register of Clans, some of whom have their own clan societies or associations:
LangSyne Publishers, who are based in Kilbarrack, Dublin, Ireland, have published individual books on the following Irish clan surnames and their histories: Barry, Boyle, Brady, Brennan, Burke, Byrne, Callaghan, Carroll, Casey, Cassidy, Clancy, Collins, Connolly, Coyle, Daly, Devlin, Doherty, Donnelly, Donovan, Doran, Doyle, Duffy, Dunne, Farrell, Fitzgerald, Fitzpatrick, Flaherty, Flanagan, Flynn, Foley, Gallagher, Griffin, Healy, Higgins, Hogan, Joyce, Kane, Kavanagh, Kelly, Kennedy, Kenny, Lynch, Maguire, Malone, McCarthy, McCormick, McDermott, McGrath, McGuigan, McKenna, McLoughlin, McMahon, McManus, McNamara, Moore, Moran, Mullan, Murphy, Nolan, O'Brien, O'Dowd, O'Dwyer, O'Grady, O'Halloran, O'Hara, O'Keeffe, O'Leary, O'Neill, O'Rourke, O'Shea, O'Connor, Quinn, Reagan, Reilly, Rooney, Ryan, Sheehan, Sheridan, Sullivan, Sweeney, Traynor, Walsh, Ward, Whelan.
John Grenham in his 1993 book, Clans and Families of Ireland: The Heritage and Heraldry of Irish Clans and Families, lists the following Irish clan surnames and gives at least a paragraph of information for each: Aherne, Allen, Armstrong, Barrett, Barry, Beatty, Bell, Boyd, Boyle, Bradley, Brady, Breen, Brennan, Browne, Buckley, Burke, Burns, Butler, Byrne, Cahill, Campbell, Carroll, Casey, Cassidy, Clancy, Clarke, Cleary, Coleman, Collins, Conlon, Connolly, Conway, Corcoran, Costello, Coughlan, Craig, Cronin, Crowley, Cullen, Cunningham, Curran, Daly, Delaney, Dempsey, Dillon, Doherty, Dolan, Donnelly, Doran, Dowd, Dowling, Doyle, Driscoll, Duffy, Duggan, Dunne, Dwyer, Egan, Fahy, Farrell, Ferguson, Finnegan, Fitzgerald, Fitzpatrick, Flaherty, Flanagan, Fleming, Flynn, Foley, Ford, Fox, Gallagher, Gorman, Graham, Greene, Griffin, Hall, Hamilton, Hayes, Healy, Hegarty, Hennessy, Henry, Hickey, Higgins, Hogan, Hughes, Hurley, Johnston, Jones, Joyce, Kane, Kavanagh, Keane, Kearney, Keating, Kelleher, Kelly, Kennedy, Kenny, Keogh, Kerr, Kiely, King, Leary, Lee, Lenehan, Lennon, Long, Lynch, Lyons, MacAuley, MacBride, MacCabe, McCann, MacCarthy, MacCormack, MacCullagh, MacDermot, MacDonagh, MacDonald, MacDonnell, MacEvoy, MacGillcuddy, MacGovern, MacGowan, MacGrath, MacGuiness, MacHugh, MacKenna, MacKean, MacLoughlin, MacMahon, MacManus, MacNally, MacNamara, Madden, MacGee, Maguire, Maher, Malone, Martin, Meehan, Molloy, Moloney, Monaghan, Mooney, Moore, Moran, Morgan, Moraiarty, Morris, Mullan, Mulligan, Murphy, Murray, Nolan, O'Brien, O'Callaghan, O'Connell, O'Connor, O'Donnell, O'Donoghue, O'Donovan, O'Grady, O'Hara, O'Keefe, O'Mahony, O'Neill, O'Rourke, O'Shea, O'Sullivan, O'Toole, Patterson, Power, Quigley, Quinn, Redmond, Regan, Reid, Reilly, Riordan, Robinson, Roche, Rogers, Rooney, Ryan, Scott, Sheehan, Sheridan, Smith, Stewart, Sweeney, Tobin, Wallace, Walsh, Whelan, White, Woods.