Organizers
- Iredell County Parks and Recreation
- Iredell Health Systems
- Ireland's Dream
- Irelands Toughest Muckers
- Irish Firefighter's Benevolent Association
- IrishFit Ltd
- iRock Fitness Inc
- Iron County Young Survivors
- Iron Diamond Sports, LLC
- Iron Girl Pleasant Prairie
- Iron Monkey Competition
- Iron Pine Lacrosse
- Iron Sharpeners, Inc.
- Iron Team Brooklyn
- Iron Temple CrossFit
- IronEdge Racing LLC
- Ironkidz Triathlon
- IRONWILL FOOTBALL
- Ironwood Golf Club
- iRun & Company, LLC
- iRun Productions
- iRun4Charity
- IRunTons, LLC
- Irving Marathon
- Irvington Sports Association
- Irvington Village Improvement Assn
- ISA
- Isa Running and Triathlon Club Inc.
- ISA UPSTATE
- Isabella's Giraffe Club
- Isaiah's Run Water Sports
- ISCA
- ISFA
- Ishpeming Little League
- iSing Silicon Valley
- Islamorada Half Marathon
- Island Athletic Events, LLC
- Island City Runner
- Island HEalth & Fitness
- Island Hills Golf Club
- Island Park Little League
- Island People's Project
- Island Vibes Summer Camp
- Islander Sports Foundation
- Islanders Soccer Camp
- IslandWood
- Isle of Hope Swim Team
- Isle of Palms Connector Run
- Isle of Wight County Parks & Recreation
- Isle of Wight-Smithfield-Windsor Chamber of Commerce
