Organizers
- CLE Swimming
- CleanEdison
- Clear Creek Challengers Booster Club
- Clear Creek Clippers 12U
- Clear Creek Metropolitan Recreation District
- Clear Lake City Community Association
- Clear Lake/White Pass Cross Country Camp
- Clear Space Theatre Company
- Clear Timing
- Clear Timing
- Clearbrook Golf Course
- Clearfield Revitalization Corporation
- Clearfield YMCA
- Clearwater Little League
- Cleasathon
- Cleburne Parks and Recreation
- Cleft Smiles 5k on behalf of Operation Smile
- Cleghorn fire station
- Clemmons Bicycle
- Clemson Air Force ROTC
- Clemson Elementary School
- Cleveland Heights Women's Hockey
- Cleveland Marathon
- Cleveland Play House
- Cleveland Pop Warner Association, Inc.
- Clickit Events, LLC
- Client Events Supported by Racine MultiSports
- Clifden Lifeboat 10k
- Cliff Brown Soccer Camps
- Cliff Drysdale Tennis at Weston Tennis Center
- Cliff Runner 10K
- Clifton Chamber of Commerce
- Clifton Park Golf Course
- Clifton Park Youth Hockey
- Clifton Park Youth Hockey Association
- Climb 4 Cancer - Mt. Washington
- Climb The Podium Events
- Clinton Chamber of Commerce
- Clinton Community YMCA
- Clinton Hickman County Chicken Festival
- Clinton River Riders
- Clinton Valley Little League
- Clinton-Gratiot Habitat for Humanity
- Clintonville Youth Baseball League
- Clio Youth Baseball
- Clippers Camps
- Clonakilty waterfront marathon
- Clonliffe Harriers
- Cloud Nine Training School for Dogs
- Clover Community Bank
