Businesses
- C Dunkley and Son Limited
- C Hugh Craven
- C Rupert Robinson, solicitor and land agent
- C Varnals and Son
- CA Peters Limited
- Cabra Catholic Institution for Deaf and Dumb
- Café Restaurant
- Cahill and Company, letterpress printers
- Callaghan's, outfitters
- Camden Picture House
- Canadian Manufacturers' Agency
- Cantwell and McDonald
- Carlington G Henry, wholesale tobacconist
- Carlton Hotel
- Carr and Son
- Carroll and Company
- Casey Clay and Collins, solicitors
- Casson and Company Limited, tea merchants
- Castle Hill Quarries (Carlingford) Limited
- Catholic and General Insurance Association Limited
- Catholic Boys Working House
- Catholic Commercial Club
- Catholic Seamen's Institute
- Catholic Truth Society of Ireland
- Cavendish Hotel
- CC Shaw, solicitor
- Cellular Clothing Company Limited
- Centenary Cooperative Dairy Society Limited
- Central Asylum
- Central Hotel
- CH Leng and Sons
- Champions Davies and Company
- Chancellor and Son, photographers
- Chapman Limited
- Charles Bewley and Company, tea merchants
- Charles J Murray, solicitor
- Charles L Reis and Company, jewellers
- Charles Morgan and Company
- Charles Nolan and Sons
- Charles Ramsay and Son, nurserymen, florists and seedsmen
- Charles Walsh, antique dealer
- Cherry and Smalldridge Limited, printers and bookbinders
- Children's Clothing Society
- Children's Hospital
- Chiswick Polish Company Limited
- Christopher Dodd and Company
- Christopher Friery, solicitor
- Church of England Institute
- Church of Ireland Printing and Publishing Company
- City and County Permanent Benefit Building Society
- City Arms Hotel
- City Hall
- City of Dublin Assurance Society
- City of Dublin Bakery
- City of Dublin Distress Committee
- City of Dublin Workingmen's Club
- City of Dublin YMCA
- Clarence Hotel
- Clarence Hotels Company Limited
- Cleary and Company, bottling warehouse
- Cleeve Brothers
- Clergy and Select Vestry
- Clery and Company Limited
- Cobbe Estate
- Colfa Gallery
- Coliseum Chambers
- Coliseum Theatre
- College Hotel
- Collen Brothers Limited
- Columbkille Co-Operative Agricultural Dairy Society
- Commissioners of Irish Lights
- Commissioners of Merrion Square
- Committee of Crown Forces Refreshments Buffet
- Committee of the Ulster Football Club
- Companions of St Patrick
- Continental Restaurant
- Convent of Mercy
- Cooper, Dennison and Walkden
- Cooperative Reference Library
- Cooperative Wholesale Society Limited
- Cork Street Hospital
- Corn Brothers
- Corneille David and Company, manufacturers and dealers in meat extracts
- Cornelius Bull Limited, manufacturers and importers of church furniture
- Corporation Dispensary
- Corporation of Dublin
- Corrigan and Wilson, printers
- Cosy Cinema Limited
- Coughlan Briscoe, solicitors
- Coventry Chain Company Limited
- Coyle Limited
- Cramer Wood and Company, pianoforte gallery and music warehouse
- Crane and Sons Limited
- Cranston and Company, wholesale stationers
- Crawford Municipal School of Art
- Croquet Club
- Crossley Brothers Limited
- Crotty's Limited
- Crowley and Bolger, solicitors
- Crown Forces' Club
- Cunningham and Kirkpatrick, agents
- Cunningham, pawnbroker
- Custom House Officials Luncheon Club
- CW Harrison and Sons, sculptors