Ó Cuirnín was the name of a brehon literary family of Breifne, related to its kings, the O'Rourkes.

The surname is now rendered Cornyn ( most commonly used Anglacised form )still quite numerous in the vicinity of Dowra in West Cavan. Courneen, Corneen, Coorneen, Curneen, or more rarely, Courtney.

• The monk O'Curnin, a pious sage, died 1258
• Tomás Ó Curnín, ollav of the Fir Brefne,, died 1400
• Cormac Ó Curnín, died 1475
• Ruaidrí Ó Curnín, died 1496
• Conor Carragh Ó Curnín, died 1498
• Ferceirtne Ó Curnín, died 1519
• Domhnall Glas Ó Curnín, died 1519