Name
- Cecil, Robert, Viscount Cranborne, 1st Earl of Salisbury, 1563-16121
- Cecil, William, 1st Baron Burghley1
- Ceith Caolriabhach1
- Chappell and Co., music publishers, 1811?-19871
- Charlemagne, of France1
- Clemens, Cyril Coniston, President International Mark Twain Society, 1902-19991
- Clonmacnoise Monastery, Offaly1
- Collas, John, FRS, of Berlin1
- Colman, Father Daniel1
- Colmer, Francis, tutor of A and C Bax1
- Commin, Faithful, supposed Dominican Friar1
- Comyn, Nicholas, Bishop of Lismore and Waterford1
- Conroy, Florence, alias Conry; Archbishop of Tuam1
- Conwye, Cahill1
- Cooke, Arnold Atkinson, composer, 1906-20051
- Cotter, James1
- Cotter, James, 1st Baronet 1763, student of Trinity College, Dublin1
- Courcey, Edward1
- Courci, John, conqueror of Ulster; d.?1219, d 12191
- Cowper, William, FRS, Surgeon and Anatomist, 1666-17091