| Abbreviation | Definition |
|---|---|
| ICPOA | Illinois Conservation Police Officers Association |
| ICR | Information Collection Rule |
| ICR | Investigate, Capture, and Recommend |
| ICRP | International Commission on Radiological Protection |
| ICS | In Constant Situation |
| ICVA | Independent Custody Visitors Association |
| ID | Identification Division |
| ID | Interesting Device |
| IDB | Illicit Diamond Buying |
| IDEA | Improvement and DEvelopment Agency |
| IDSI | Involuntary Deviate Sexual Intercourse |
| IDTU | Intoxicated Driver Testing Unit |
| IDU | Injecting Drug User |
| IED | Improvised Explosive Device |
| IFIS | Integrated Forensic Identification Services |
| IFN | Information Force Network |
| IFO | In Front Of |
| IFS | Institute of Forensic Sciences |
| IIB | Integrated Investigative Bureau |
| IIC | Internal Investigation Command |