Schools

• Central Catholic High School (Allentown, Pennsylvania)
• Camden Catholic High School (Cherry Hill, New Jersey)
• Cathedral Catholic High School (San Diego, California)
• Catholic Central High School
• Central Cabarrus High School (Concord, North Carolina)
• Central Catholic High School (Toledo, Ohio)
• Chambly County High School (now Chambly Academy) (Saint-Lambert, Canada)
• Charlotte Catholic High School (Charlotte, North Carolina)
• Chelmsford County High School for Girls (Chelmsford, England)
• Cherry Creek High School (Greenwood Village, Colorado)
• Chilton County High School (Clanton, Alabama)
• Christian Community High School (Sydney, Australia)
• Christopher Columbus High School (Miami, Florida)
• Clarke County High School (Berryville, Virginia)
• Codsall Community High School, (South Staffordshire, England)
• Colchester County High School, (Essex, England)
• Columbia City High School (Columbia City, Indiana)
• Concord-Carlisle High School (Concord, Massachusetts)
• Cooper City High School (Cooper City, Florida)
• Cornwall Central High School (Cornwall, New York)
• Covenant Christian High School (Indianapolis, Indiana)
• Cramlington Community High School (Cramlington, England)
• Cross Creek High School (Augusta, Georgia)
• Culpeper County High School (Culpeper, Virginia)
• Culver City High School (Culver City, California)
• Central Catholic High School (Wheeling, West Virginia)

Other

• Carleton County Historical Society (New Brunswick, Canada)
• Congenital Central Hypoventilation Syndrome, a disorder in which hypoventilation is a primary symptom