| Name | Medien | | C.A. Starke Verlag, Limburg | 1 |
| Candels, Heinrich | 1 |
| Carl, Marie-Luise | 1 |
| Carl Lange Verlag Duisburg | 1 |
| Carp Schule, Duisburg-Ruhrort | 1 |
| Carstanjen, Conrad Jacob | 1 |
| Caspari, Fritz | 1 |
| Caspary, Hans | 1 |
| Caspary, Walter | 2 |
| Caspers, Gerhard | 2 |
| Cassou, Jean | 0 |
| Castendyk geb. Backhaus, Hedwig | 1 |
| Cercle Généalogique Yutz 3 Frontières | 1 |
| Christ, Magdalene | 4 |
| Christmann, Ernst | 2 |
| Christoffel, Edgar | 2 |
| Christoffel, Karl | 3 |
| Clark, Christopher | 1 |
| Claßen, Robert | 1 |
| Clemen, Paul | 15 |
| Clemens, Hans | 1 |
| Cleve, Prof. Ernst | 1 |
| Clodius, Siegfried | 2 |
| Cloß, Gustav Adolf | 2 |
| Clostermann, Heinrich | 1 |
| Clotten, Jakob | 1 |
| Cnyrim, Constantin | 3 |
| Collinet-Schmittwenzl, Rosie | 1 |
| Comes, Hans | 2 |
| Conen, Marie-Luise | 4 |
| Conen, Werner | 1 |
| Conrad, Hermann | 1 |
| Conrad, Horst | 1 |
| Conrad, Otto | 1 |
| Convents, F. J. | 1 |
| Conze, Werner | 1 |
| Coors, Dr. Dieter | 3 |
| Corall, Peter | 1 |
| Cornelissen, Dr. Georg | 5 |
| Corsten, Hermann | 1 |
| Corsten, Severin | 5 |
| Corsten, Wilhelm | 2 |
| Courts, Gerd | 1 |
| Couvreur, Rudy | 1 |
| Cox, Erich | 1 |
| Cox, Dr. Henry Th. | 1 |
| Craemer, Annette | 6 |
| Cramer, Rudolf | 1 |
| Cremer, Sibylle | 94 |
| Croon, E. | 1 |
| Croon, Maria | 10 |
| Crott, Jos | 2 |
| Cüppers, Heinz | 5 |
