- Chatfield & Woods1
- Chattanooga Paint Company1
- Chicago Bakery Company1
- Chicago Label Box Company1
- Chicago Title & Trust Company1
- Cincinnati Pump Co.1
- Cincinnati Tin & Japan Company1
- Cincinnati, Hamilton, and Dayton Railroad Company1
- Citizen's National Bank2
- Citizens National Bank of New York1
- City Mills Company1
- Claflen Paving Co.1
- Clark & Wilkins Co.1
- Clark, Adams & Clark1
- Clarke & Courts Manufacturing Stationers1
- Clarke & Jones1
- Clarke Bros. & Co.3
- Cleveland Window Glass Co.1
- Cole & Gilpin1
- Collins Plow Company2
- Columbia Bank1
- Columbia Hall1
- Columbia Machine Works1
- Columbia National Bank1
- Columbus Bolt Works & Co.1
- Colwell Lead Company1
- Congdon & Carpenter Co.1
- Consolidated Engineering Co.1
- Cook House1
- Cornell Wood Products Company1
- Cornet & Nightengale1
- Cornish Co.1
- Cortland Wagon Co.1
- Cosmopolitan Hotel1
- Cousens & Tomlinson1
- Cowing & Co.2
- Craddock-Terry Company1
- Craffey and Crowell1
- Crandall & Morrison2
- Crane & Breed Mfg. Co.1
- Crane & Hurd3
- Crescent Candy Company1
- Crocker & Eldridge1
- Crocker & Ogden1
- Croft Brothers1
- Crompton Loom Works1
- Crook's Bakery and Restaurant1
- Cross Brothers Company1
- Crystal Window Glass Works1
- Cumberland Mills1
- Cunningham, Frost & Throckmortons1
- Curry, Tunis & Norwood1
- Curtis & Curtis Co.1
- Curtis & Rickerson1
- Cushing, Olmsted and Snoss2
- Cutler & Neilson Paint & Color Co.1
- Cutler & Porter1
- Cutler Paint & Glass Co.1
- D'Acheul Drug Company1
- D. Auerbach & Sons1