Eastern Idaho Cooperative Agencies Wireless Interoperable Network (EICAWIN)
From The RadioReference Wiki
System Notes
Although this is a standalone system it allows for full interoperability with the state ICAWIN TRS. It also allows for interoperability with previously existing Fire and EMS VHF radio systems in these counties.
This PDF document is a description of the radio system as provided by the system supplier. Included is an Idaho county map showing the counties participating in this system.