- CARADOG FYNACH (d. 1124), recluse
- CARANNOG (fl. 550?), saint
- CARBERY, Earls of - see VAUGHAN
- CARN INGLI - see HUGHES, JOSEPH
- CARNE, Sir EDWARD (c. 1500 - 1561), lawyer and diplomat
- CARNE, THOMAS, M. P. - see CARNE, Sir EDWARD
- CARNEDDOG - see GRIFFITH, RICHARD
- CARNEINION - see EVANS, JAMES
- CARNELIAN - see COSSLETT, COSSLETT
- CARNES, EDWARD (1772? - 1828), bookseller and printer
- CARNES, WILLIAM, bookbinder - see CARNES, EDWARD
- CARNHUANAWC - see PRICE, THOMAS
- CARPENTER, KATHLEEN EDITHE (1891 - 1970), ecologist
- CARR, HENRY LASCELLES (1841 - 1902), journalist and newspaper proprietor
- CARRINGTON, THOMAS (Pencerdd Gwynfryn; 1881 - 1961), musician and printer
- CARTER family Kinmel,
- CARTER, HUGH (1784 - 1855), Welsh Wesleyan Methodist minister
- CARTER, ISAAC (d. 1741), printer
- CARTER-JONES, LEWIS (1920 - 2004), Labour politician
- CARW COCH - see WILLIAMS, WILLIAM
- CASNODYN (fl. 1320-40), poet
- CASNODYN - see STEPHENS, THOMAS
- CASSON, LEWIS (1875 - 1969), actor and theatrical producer
- CATHERALL, JONATHAN (1761 - 1833), industrialist and philanthropist
- CATRIN ferch GRUFFUDD ap HYWEL (fl. c. 1555), poet
- CATRIN ferch GRUFFYDD ap IEUAN [ap LLYWELYN?] FYCHAN (fl. 16th century), poet
- CATWG - see WILKINS, CHARLES
- CAWDOR, Earl - see CAMPBELL, F. A. V.
- CAWR CYNON - see EVANS, WILLIAM
- CAWRDAF - see JONES, WILLIAM ELLIS
- CAYO-EVANS, WILLIAM EDWARD JULIAN (1937 - 1995), political activist
- CECIL family Allt-yr-ynys, Burghley, Hatfield, Northampton)
- CECIL-WILLIAMS, Sir JOHN LIAS CECIL (1892 - 1964), solicitor, secretary Honourable Society of Cymmrodorion and driving force behind the publishing of the Dictionary of Welsh Biography
- CEFNI - see PARRY, HUGH
- CEIRIOG - see HUGHES, JOHN CEIRIOG
- CELATUS - see OWEN, OWEN
- CELT - see HUMPHREYS, EDWARD MORGAN
- CELTIC DAVIES - see DAVIES, EDWARD
- CELYNOG - see WILLIAMS, RICHARD
- CEMLYN-JONES, Sir ELIAS WYNNE (1888 - 1966), public figure
- CERIDWEN PERIS - see JONES, ALICE GRAY
- CEULANYDD - see WILLIAMS, JOHN CEULANYDD
- CHALONER, JACOB (1586 - 1631), herald - see CHALONER, THOMAS
- CHALONER, ROBERT (1612 - 1675), herald - see CHALONER, THOMAS
- CHALONER, THOMAS (d. 1598), Ulster King of Arms
- CHAMBERS, JOHN GRAHAM (1843 - 1883), athlete - see CHAMBERS, WILLIAM
- CHAMBERS, WILLIAM (1774 - 1855), industrialist and public figure
- CHAMBERS, WILLIAM (1809 - 1882), magistrate - see CHAMBERS, WILLIAM
- CHANCE, THOMAS WILLIAMS (1872 - 1954), minister (B) and principal of the Baptist College, Cardiff
- CHAPPELL, EDGAR LEYSHON (1879 - 1949), sociologist, a pioneer of town and village redevelopment, and writer