- Cambridge1
- Canyon near museum, Colton's "Coyote Ranch,"1
- Cave Creek, Middle St. Vrain1
- Cedar Bend Park, 3 miles NW of Waverly, near Cedar River1
- Chippewa1
- Clearwater1
- Coamo1
- Cochise1
- Cojo cañon, on coast about 10 miles north of Santa Cruz1
- Colfax1
- Colima1
- Colorado National Monument. Kodel Canyon, north-facing, just west of the Fruita entrance. On sloping face of a large sandstone block fallen from the canyon wall, near the canyon floor along an Intermittent stream1
- Columbus1
- Comox, near the sea1
- Conejos1
- Conway1
- Cornwall Bridge1
- Custer1
- Dane1
- Dos Bocas above Corozal, Cordillera Central1