| CASTLEHILL | OS1/23/16/228 |
| CASTLEHILL | OS1/23/16/70 |
| CAT HILL | OS1/23/16/129 |
| CATAGREEN | OS1/23/16/74 |
| CAVADY | OS1/23/16/10 |
| CAVE GEO | OS1/23/16/118 |
| CAVE OF THE TWENTY MEN HOLE | OS1/23/16/117 |
| CAVIT | OS1/23/16/260 |
| CHAPEL (In Ruins) [Eynhallow] | OS1/23/16/140 |
| CHAPEL (In Ruins) [nr Castle of Cobbie Roo] | OS1/23/16/242 |
| CHURCH (In Ruins) [Skaill] | OS1/23/16/125 |
| CHURCH KNOWE | OS1/23/16/193 |
| CHURCH [nr Cott] | OS1/23/16/239 |
| CLASSIQUOY | OS1/23/16/215 |
| CLAYBANK | OS1/23/16/43 |
| CLAYPOTS | OS1/23/16/26 |
| CLINK GEOS | OS1/23/16/51 |
| CLUMPY | OS1/23/16/160 |
| COBBIE ROW'S BURDEN | OS1/23/16/206 |
| COGAR | OS1/23/16/40 |
