| Institute for Competitive State Government | Academic & Science |
| Irish Centre for Social Gerontology | Academic & Science |
| International Center for Self-Governance | Academic & Science |
| Internet Chemistry Sites Gopher | Academic & Science |
| International Copper Study Group | Academic & Science |
| Independent Contractor Specialist Group, L.L.C. | Business |
| International Consulting Security Group | Business |
| International Corporate Services Group | Business |
| Internet Communications Software Group | Business |
| Intelligent Computer Software Group | Business |
| Independent Contractor Specialist Group | Business |
| Interfaith Center for Spiritual Growth | Community |
| Interstitial Cystitis Support Group | Community |
| International Society of Guatemala Collectors (stamp collecting) | General |
| International Cleaning Solutions Group | General |
| Industry Connections Security Group | General |
| Integrated Circuits and Systems Group | General |
| Integrated Communications System Group | General |
| Idaho Child Support Guidelines | General |
| ICAO Cabin Safety Group | General |
| Internal Campaign Steering Group | General |
| International Consortium for Scoliosis Genetics | General |
| Ideal Child Services Group | General |
| Inventory of Complicated Spiritual Grief | General |
| Integrated Communications Systems Group | General |
| Indiana Child Support Guidelines | General |
| International Council of Surgical Gastroenterology | Governmental |
| International Conference on Sustainable Globalization | International |
| International Consortium on Sunflower Genomics | International |
| International Cooperative Study Group | International |
| Iranian Cancer Support Group | Medical |
| Internet Cancer Support Group | Medical |
| Irish Centre for | Regional |
