- Buckingham, Bucks County, Pennsylvania, United States1
- Bucks County, Pennsylvania, United States3
- Cairo, Egypt1
- Caldbeck Fells, Cumberland, Cumbria, England, United Kingdom1
- California, United States1
- Campania, Rome Province, Italy1
- Canada2
- 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
- Charlottesville, Virginia, United States2
- 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