Organizers
- Carlisle Parks and Recreation
- Carolina Tactical Training
- Carpet Capital Running Club
- Carroll Area Swim Team
- Carroll ISD Aquatic Center
- Carson City Parks, Recreation and Open Space
- CASMA Toronto
- Casper Recreational Leagues Association
- Castlegar Aquanauts
- Castroville, Texas
- Catholic Challenge Sports
- Catholic University Women's Lacrosse
- CATS CAMPS
- CATS School Year Programs
- Cayuga Nature Center
- CCE Paddling Club
- Cedar Ridge Equine, Inc
- Center For The Creative Arts
- CenterStage Theater Company
- Central Alabama Firearms Training LLC
- Central Coast Tennis
- Central Connecticut Arms, LLC
- Central Dauphin Area Basketball Association
- Central Lincoln County Adult Education
- Central Texas Tennis Association
- Central Youth Softball Association
- Centralia Parks & Recreation
- Centralized Equipment Pool
- CentralOnline.tv
- Centre des arts Shenkman Arts Centre
- Chagrin Falls Community Education
- Champions Hockey Academy Inc.
- Charlotte Tennis Association
- Charlottesville Waldorf School
- Chaska Parks & Recreation
- Chatham Sports Camps
- Chatham Youth League
- Chattanooga Zoo
- Cheer Tech - Spirit Brands
- Cheer Your Heart Out GA
- Chef Walters Cooking School
- Chehalem Parks and Recreation
- Chelsea Hall Academic Learning Center
- Cheltenham Center for the Arts
- Cherry Point Aquatics
- Cherry Point Youth Sports
- Chesapeake Bay Sports Camps
- Chesapeake Parks, Recreation and Tourism
- Chess Tutors After School Programs
- Chess Tutors Grand Match Gala
