| ICGS | Immaculate Conception Grade School 
| Others |
| ICGS | Improved Conjugate Gradient Squared
| Others |
| ICGS | Independent Coin Grading Service
| Others |
| ICGS | Ingham County Genealogical Society
| Others |
| ICGS | Integrated Coast Guard Systems
| Others |
| ICGS | Intelligent Computer Graphics System
| Others |
| ICGS | Interactive Computer Graphics System
| Others |
| ICGS | International Catholic Girls' Society
| Others |
| ICGS | International Center For Gibbon Studies
| Others |
| ICGS | International Center For Graduate Studies
| Others |
| ICGS | International Centre for Geopolitical Studies
| Others |
| ICGS | International Centre For Graduate Studies
| Others |
| ICGS | International Chromosome and Genome Society
| Others |
| ICGS | International Classification of Goods and Services
| Others |
| ICGS | International College And Graduate School
| Others |
| ICGS | International Congress on Glaucoma Surgery
| Others |
| ICGS | International Corporate Governance Society
| Others |
| ICGS | International Cytogenetic And Genome Society
| Others |
| ICGS | International Cytogenetics And Genome Society
| Others |
| ICGS | Ional College Graduate School
| Others |
| ICGS | Ionia County Genealogical Society
| Others |
| ICGS | Iowa City Girls Softball
| Others |
| ICGS | Iowa City Girls' Softball
| Others |
| ICGS | Isinternational Centre For Geopolitical Studies
| Others |
| ICGS | Italian Citizenship and Genealogy Services
| Others |
| ICGS | Italian Citizenship Genealogy Services
| Others |