- California, United States1
- Campania, Rome Province, Italy1
- Carbon (Northampton) County, Pennsylvania, United States1
- Castleton, Derbyshire, England, United Kingdom1
- Cayuga Lake, New York, United States1
- Cayuga River, New York, United States1
- Charlotte, Mecklenburg County, North Carolina, United States1
- Chemnitz, Saxony, Germany (Hungary)1
- Chesapeake Bay, Maryland, Virginia, United States1
- Cheshire, New Haven County, Connecticut, United States1
- Cheshire, New Haven, Connecticut, United States1
- Chessy Copper mines, Chessy, Rhône-Alpes, France 1
- Chester County, Pennsylvania1
- Chester County, Pennsylvania, United States1
- Chester, Chester County, Pennsylvania, United States1
- Chesterfield, Hampshire County, Massachusetts, United States1
- Clarksville, Habersham County, Georgia, United States1
- Connecticut, United States1
- Copiapo, Atacama, Chile1
- Copper Mine Hill, Cumberland, Providence County, Rhode Island, United States1