| 1898-Main | Conneaut Water Co | Pumping station | Harbor | |
| 1407-White | Conneaut Water Co. | Shop | 509 Liberty st | |
| 1967-Red | Connell, J. L. | Res. | West Main st | |
| 1551-Black | Conners, E. D. | Res. | 459 Madison st | E. Conn. |
| 1573-Black | Cook, I. C. | Res. | 236 Mill st | |
| 1570-Red | Cook, J. P. | Res. | 663 Main st | |
| 1541-Red | Cool, Chas. H. | Res. | 700 Lake View ave. | N. Conn |
| 1197-North | Cool, H. E. | Res. | 620 Lake View ave. | |
| 1815-Main | Coon, F. L. | Grocer | Chadman blk.. >>>>>> |
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| 1915-Main | Coon, F. L. | Grocery | Chadman blk. | |
| 1743-White | Coon, Fl L. | Res. | 184 Washington st | |
| 1472-Black | Cooney, O. B. | Res. | 600 Mill st | |
| 1275-White | Cooper, C. M. | Res. | 451 Liberty st | |
| 1551-Blue | Cooper, H. J. | Res. | 307 Chestnut st | |
| 1142-Main | Cornell, H. E. | Res. | 361 Adams st | |
| 1131-Main | Cossitt, Dr. D. S. | Res. | 229 Sandusky st | |
| 1412-Blue | Cottingham, J. C. | Res. | 180 School st | |
| 1121-Red | Coghlan, Mrs. F. T. | Res. | 298 Liberty st | |
| 1966-Main | Coughlan's Livery | 181 Main st | ||
| 1416-Black | Coughlan, Wm. | Res. |
442 Harbor st (See note (1) below.) >>>>>> |
 |
| 1338-Black | Countryman, E. | Res. | 168 Main st | |
| 1431-White | Cousins, Nick | Res. | 439 Monroe st | |
| 1551-White | Cousins, R. M. | Res. | 511 Madison st | |
| 1520-Blue | Coville, Alice | Res. | 184 Harbor st | |
| 1557-White | Coville, K. R. | Res. | 171 Liberty st | |
| 1413-Black | Cowden, K. W. | Res. | 395 Harbor st | |
| 1615-Blue | Cowen, C. C. | Res. | 749 Harbor st | |
| 1389-Red | Cowle, J. T. | Res. | 164 Poplar st | |
| 1180-Main | Cox, Mrs. A. M. | Res. | 208 Liberty st | |
| 1439-White | Coyne, W. J. | Res. | 491 Madison st | |
| 1998-Main | Craftsman Tool Co., The | Office | Cor. Mill & Bliss ave. | |
| 1621-Main | Craig, Jay | Res. | 138 15th st | |
| 1356-Blue | Cramer, C. V. | Res. | 317 Madison st | |
| 1561-Black | Crane, Mrs. Mary | Res. | 769 Main st | |
| 1293-Blue | Cray, J. Ralph | Res. | 314 Buffalo st |