| Island's Name | Island group | Country/Dependency |
| Caballo | Manila Bay | Philippines |
| Cabanaas | Algarve islands | Portugal |
| Cabbage | Holston River, Tennessee | United States |
| Cabrera | Balearic Islands | Spain |
| Cacela | Algarve islands | Portugal |
| Caillou | Timbalier Bay, Louisiana | United States |
| Caja de Muertos | Puerto Rico | United States |
| Calayan | Babuyan Islands, Cagayan | Philippines |
| Calf of Eday | The North Isles, Orkney Islands | United Kingdom, Scotland |
| Calf of Flotta | The South Isles, Orkney Islands | United Kingdom, Scotland |
| Calf of Man | Isle of Man | Crown dependency |
| Callinan | Stoney Lake, Ontario | Canada |
| Calumet | Timbalier Bay, Louisiana | United States |
| Calvert | British Columbia | Canada |
| Cambalhão | Estremadura islands | Portugal |
| Camelot | St. Lawrence River, Ontario | Canada |
| Cameron | Nunavut | Canada |
| Cameron | Lake Joseph, Ontario | Canada |
| Camiguin Island | Mindanao | Philippines |
| Camiguin de Babuyanes | Babuyan Islands, Cagayan | Philippines |
| Camorta | Central group of the Nicobar Islands | India |
| Camp | Lake Winnipesaukee, New Hampshire | United States |
| Campania | British Columbia | Canada |
| Campbell | Torres Strait Islands, Queensland | Australia |
| Campbell | Campbell Islands | New Zealand |
| Campbell | British Columbia | Canada |
| Campbells | Mississippi River, Illinois | United States |
| Campobello | New Brunswick | Canada |
| Cancún | Caribbean, Quintana Roo | Mexico |
| Candlana Bar | Willamette River, Oregon | United States |
| Canna | Inner Hebrides | United Kingdom, Scotland |
| Isla del Caño | Bahia de Coronado | Costa Rica |
| Cannon Rock | | Northern Ireland |
| Cantin | French River, Ontario | Canada |
| Cape Barren | Furneaux Group, Bass Strait, Tasmania | Australia |
| Cape Breton | Nova Scotia | Canada |
| Capraia | Tuscan Archipelago | Italy |
| Caprara | Tremiti Islands | Italy |
| Caprera | Maddalena archipelago, Sardinia | Italy |
| Capri | Gulf of Naples | Italy |
| Car | Lower Lough Erne | Ireland |
| Car Nicobar | Northern group of the Nicobar Islands | India |
| Cara | Inner Hebrides | United Kingdom, Scotland |
| Carcass | Falkland Islands | United Kingdom |
| Isla Carmen | Baja California Sur | Mexico |
| Carmen | Laguna de Términos, Campeche | Mexico |
| Carmines | York River, Virginia | United States |
| Carmona | Beira Baixa islands | Portugal |
| Caroline | Line Islands | Kiribati |
| Carpmael | Georgian Bay, Ontario | Canada |
| Carrington | Great Salt Lake, Utah | United States |
| Carroll | Mississippi River, Illinois | United States |
| Isla de La Cartuja | Guadalquivir River, Seville, Andalusia | Spain |
| Cascalheira | Alentejo islands | Portugal |
| Casse-Tete | Timbalier Bay, Louisiana | United States |
| Cast-off | Allegheny River, Pennsylvania | United States |
| Cat | Bahamas | Bahamas |
| Cat | Mascarene Islands | Mauritius |
| Cat | Mississippi River, Arkansas | United States |
| Cat | Apostle Islands, Wisconsin | United States |
| Cat | Gulf Coast, Mississippi | United States |
| Cát Bà | Hạ Long Bay | Vietnam |
| Catalina | Channel Islands of California, California | United States |
| Catalina De La Romana | La Romana | Dominican Republic |
| Çatalada | Aegean Sea | Turkey |
| Catanduanes | Catanduanes, Luzon | Philippines |
| Catfish | Missouri River, Missouri | United States |
| Caye Caulker | Caribbean | Belize |
| Cava | Orkney Islands | United Kingdom, Scotland |
| Caviana | Mouth of the Amazon River, Pará | Brazil |
| Cavus adasi | Kiremit islands group | Turkey |
| Cayman Brac | Cayman Islands | United Kingdom |
| Cebu | Visayas | Philippines |
| Cedar | St. Lawrence River, Ontario | Canada |
| Cedar | Willamette River, Oregon | United States |
| Cedros | Pacific Ocean, Baja California | Mexico |
| Central Coronado | Coronado Islands, Baja California | Mexico |
| Center | San Juan Islands, Washington | United States |
| Centre | Georgian Bay, Ontario | Canada |
| Cerf | Seychelles | Seychelles |
| Cessions Towhead | Mississippi River, Arkansas | United States |
| Cezi | Zhoushan | China |
| Chafarinas | Plazas de soberanía, Strait of Gibraltar | Spain |
| Champlain | Georgian Bay, Ontario | Canada |
| Champlain Monument | Georgian Bay, Ontario | Canada |
| Chandeleur | Louisiana | United States |
| Chandra | Bajuni Islands | Somalia |
| Ko Chang | Gulf of Thailand | Thailand |
| Changbai | Zhoushan Archipelago | China |
| Change | Newfoundland and Labrador | Canada |
| Changzhi | Zhoushan Archipelago | China |
| Chantry | Lake Huron, Ontario | Canada |
| Charles | Nunavut | Canada |
| Charles | Connecticut | United States |
| Charlton | Nunavut | Canada |
| Chases | Lake Winnipesaukee, New Hampshire | United States |
| Chausey | Channel Islands | France |
| Cheduba | | Myanmar |
| Chek Lap Kok | Hong Kong | China |
| Chełminek | Oder Lagoon islands | Poland |
| Chelat | Lakshadweep | India |
| Chergui | Kerkenna Islands | Tunisia |
| Cheung Chau | Islands District, Hong Kong | China |
| Chick | Lake Erie, Ontario | Canada |
| Chicot | Louisiana | United States |
| Chief's | Lake Joseph, Ontario | Canada |
| Chiefs | Lake Couchiching, Ontario | Canada |
| Chillicothe | Illinois River, Illinois | United States |
| Chiloane | | Mozambique |
| Chiloé | Chiloé Archipelago | Chile |
| Isla Chincha Centro | Chincha Islands | Peru |
| Isla Chincha Norte | Chincha Islands | Peru |
| Isla Chincha Sur | Chincha Islands | Peru |
| Chios | Aegean Islands | Greece |
| Chira | Gulf of Nicoya | Costa Rica |
| Chirinkotan | Kuril Islands Sakhalin Oblast | Russia |
| Chirpoy | Kuril Islands Sakhalin Oblast | Russia |
| Chizumulu | Lake Malawi | Malawi |
| Choctaw Island No. 78 | Mississippi River, Arkansas | United States |
| Choiseul | Melanesia | Solomon Islands |
| Choupique | Louisiana | United States |
| Chouteau | Mississippi River, Illinois | United States |
| Chovaye | Bajuni Islands | Somalia |
| Chowra | Central group of the Nicobar Islands | India |
| Christian | Georgian Bay, Ontario | Canada |
Christmas  | Indian Ocean | Self-governing Territory of Australia |
| Chrysi | | Greece |
| Cula | Bajuni Islands | Somalia |
| Churchill | Georgian Bay, Ontario | Canada |
| Cicia | Lau Islands of Fiji | Fiji |
| Čiovo | | Croatia |
| Île de la Cité | Seine River, Paris | France |
| City | Halifax River, Florida | United States |
| City | Florida | United States |
| City | Mississippi River, Iowa | United States |
| City | The Bronx, New York | United States |
| City | Susquehanna River, Pennsylvania | United States |
| Clackamette | Willamette River, Oregon | United States |
| Clare | Clew Bay islands | Ireland |
| Clarence | South Shetland Islands | Claimed by Argentine Antarctica, Argentina, Antártica Chilena Province of Chile, and the British Antarctic Territory of the United Kingdom |
| Isla Clarión | Revillagigedo Islands, Colima | Mexico |
| Clarion | Allegheny River, Pennsylvania | United States |
| Clark | San Juan Islands, Washington | United States |
| Clarksville | Mississippi River, Illinois | United States |
| Clear | | Ireland |
| Cleenishmeen | Lower Lough Erne | Ireland |
| Clipperton | Pacific Ocean | France |
| Clooney | Louisiana | United States |
| Cloquet | Mississippi River, Minnesota | United States |
| Club | Georgian Bay, Ontario | Canada |
| Club | St. Lawrence River, Ontario | Canada |
| Coats | Nunavut | Canada |
| Cobra | Algarve islands | Portugal |
| Coburg | Nunavut | Canada |
| Cockburn | Lake Huron, Ontario | Canada |
| Cayo Coco | Greater Antilles | Cuba |
| Coco | Algarve islands | Portugal |
| Cocos | Pacific Ocean | Costa Rica |
| Cocos | Guam | United States |
| Cod | Newfoundland and Labrador | Canada |
| Coelleira | Galicia | Spain |
| Coëtivy | Seychelles | Seychelles |
| Cogley | Allegheny River, Pennsylvania | United States |
| Coiba | Veraguas | Panama |
| Coleman | Mississippi River, Illinois | United States |
| Coll | Inner Hebrides | United Kingdom, Scotland |
| Collanmore | Clew Bay islands | Ireland |
| Colonsay | Inner Hebrides | United Kingdom, Scotland |
| Comfort | Louisiana | United States |
| Comino | Kemmuna, Maltese Islands | Malta |
| Cominotto | Maltese Islands | Malta |
| Côn Sơn | Côn Đảo | Vietnam |
| Conanicut | Narragansett Bay, Rhode Island | United States |
| Conception | Seychelles | Seychelles |
| Conejera | Balearic Islands | Spain |
| Conejo | Gulf of Fonseca | Honduras |
| Constance Island | St. Lawrence River, Ontario | Canada |
| Constance Island | Andaman Islands, Indian Ocean | India |
| Isla Contadora | Pearl Islands | Panama |
| Cook | | Cook Islands(self-governing in free association with New Zealand) |
| Coon | Mississippi River, Illinois | United States |
| Coon | Louisiana | United States |
| Copinsay | Orkney Islands | United Kingdom, Scotland |
| Coquet | England | United Kingdom |
| Coreille | Ottawa River, Ontario | Canada |
| Corfu | Ionian Islands | Greece |
| Corisco | Río Muni estuary | Equatorial Guinea |
| Corn Holm | Orkney Islands | United Kingdom, Scotland |
| Cornwall | Nunavut | Canada |
| Cornwall | St. Lawrence River, Ontario | Canada |
| Cornwallis | Nunavut | Canada |
| Cornwallis | South Shetland Islands | Claimed by Argentine Antarctica, Argentina, Antártica Chilena Province of Chile, and the British Antarctic Territory of the United Kingdom |
| Coron | | Philippines |
| Coronation | South Orkney Islands | Claimed by the United Kingdom as part of the Falkland Islands and by Argentina |
| Corratistune | Upper Lough Erne | Ireland |
| Corregidor | Manila Bay | Philippines |
Corsica  | | France |
| Cortes | Discovery Islands, British Columbia | Canada |
| Corvo | Azores | Portugal |
| Cosmoledo | Outer Islands of the Seychelles | Seychelles |
| Cotnam | Ottawa River, Ontario | Canada |
| Cottel | Newfoundland and Labrador | Canada |
| Cottonwood Bar | Mississippi River, Louisiana | United States |
| Couba | Mississippi River, Louisiana | United States |
| Coughran's | Lower Lough Erne | Ireland |
| Courson | Allegheny River, Pennsylvania | United States |
| Cousin | Seychelles | Seychelles |
| Cousine | Seychelles | Seychelles |
| Cove | Lake Huron, Ontario | Canada |
| Cove | Lake Winnipesaukee, New Hampshire | United States |
| Cow | Rice Lake, Ontario | Canada |
| Cow | Lake Winnipesaukee, New Hampshire | United States |
| Cox | British Columbia | Canada |
| Cozumel | Caribbean | Mexico |
| Cracroft | British Columbia | Canada |
| Cranberry | Lake Huron, Ontario | Canada |
| Crane | San Juan Islands, Washington | United States |
| Crawford | Georgian Bay, Ontario | Canada |
| Credit | Mississippi River, Iowa | United States |
| Cres | Adriatic Sea | Croatia |
| Crescent | Bay of Isles, South Georgia | British overseas territory |
| Crescent | Georgian Bay, Ontario | Canada |
| Crete | | Greece |
| Crevinishaughy | Lower Lough Erne | Ireland |
| Crim Rocks | Isles of Scilly | United Kingdom |
| Crooked | Florida | United States |
| Crosier | Charleston Lake, Ontario | Canada |
| Crowlin | Inner Hebrides | United Kingdom, Scotland |
| Crown | Lake Muskoka, Ontario | Canada |
| Crown Prince Frederik | Nunavut | Canada |
| Crozier | Kennedy Channel, Greenland | Denmark |
| Cruls (also known as Crulls Islands) | Wilhelm Archipelago | Antarctica |
| Crull's | Allegheny River, Pennsylvania | United States |
| Crump Island | Lesser Antilles | Antigua and Barbuda |
| Cruninish | Lower Lough Erne | Ireland |
| Cseke-sziget | Danube River | Hungary |
| Csepel-sziget | Danube River | Hungary |
| Cuba | Greater Antilles | Cuba |
| Culatra | Algarve islands | Portugal |
| Cu Lao Dung | Hau River | Vietnam |
| Culebra | Causeway Islands, Panama Canal | Panama |
| Culebrita | Culebra archipelago, Puerto Rico | United States |
| Cumberland | Ohio River, Kentucky | United States |
| Cunda | Aegean Sea | Turkey |
Curaçao  | Lesser Antilles | Kingdom of the Netherlands |
| Curieuse | Seychelles | Seychelles |
| Cuttyhunk | Elizabeth Islands, Massachusetts | United States |
| Île aux Cygnes | Seine River, Paris | France |
| Cypress | San Juan Islands, Washington | United States |
| Cyprus | Cyprus | Cyprus and Akrotiri and Dhekelia, United Kingdom sovereign base areas. ( Northern Cyprus claims and controls one third of the island, although this is not recognised by any country except Turkey.) |