- C. F. Livingston's Job Printing House1
- C. H. Cutting & Co.1
- C. H. Pepper1
- C. J. Blackstone1
- C. Kenyon Co.1
- C. Rasmussen Publishing Co.1
- C. Stewart & Son1
- C. Stolzenbach1
- C. T. Williamson Wire Novelty Co.1
- C. V. Clickener & Co.1
- C. W. Billings Slate and Wood Mantel Works1
- C. Yaeger & Co.1
- C.H. & L.J. McCormick's Reaper Manufactory1
- California Sugar Refinery1
- Campbell & Cutler Paint & Glass Co.1
- Campbell & Dick1
- Campbell Glass & Paint Co.1
- Campbell Mfg. Co.1
- Campbell, Nichols & Gwyer1
- Capewell Horse Nail Co.1
- Carbon Dioxide and Magnesia Company1
- Carey Bros. & Grevmeyer2
- Carrollton1
- Carscallen & Cassidy1
- Carson City Savings Bank1
- Castle Bro's & Loupe1
- Castle Brothers4
- Cedar Hollow Lime Company1
- Central Bank1
- Central Safe Deposit Co.1
- Champney, Brothers & Co.1
- Chapman & Soden1
- Chapman Valve Manufacturing Co.1
- Charles Baker & Co.1
- Charles Broadway House1
- Charles F. Adams1
- Charles H. Howell & Co.1
- Charles H. North & Co.1
- Charles M. Clapp & Co.1
- Charles Mayer & Co.1
- Chas. F. Baker & Co.2
- Chas. P. Willard & Co.1
- Chas. W. Freeland & Co.1
- Chase & Sanborn1
- Chicago Bakery Company1
- Chicago Label Box Company1
- Chicago Title & Trust Company1
- Cincinnati Tin & Japan Company1
- Cincinnati, Hamilton, and Dayton Railroad Company1
- Citizen's National Bank2
- Citizens National Bank of New York1
- City Mills Company1
- Clark, Adams & Clark1
- Clarke & Jones1
- Cole & Gilpin1
- Collins Plow Company1
- Columbia Bank1
- Columbia Machine Works1
- Columbia National Bank1
- Colwell Lead Company1