Railway companies of Idaho

List of railway companies in the American state of Idaho.

Companies based in the United States

 * Amtrak (AMTK), passenger on freight lines
 * Burlington Northern & Gulf Railroad (BNG), freight
 * North Western Pacific Railroad (NWP), freight and passenger
 * Union Pacific Railroad (UP), freight

Companies based outside of the United States

 * Spokane International Railroad (SI), British Columbia, freight and passenger
 * Washington & British Columbia Railway (WBC), freight and passenger

Regional railways

 * Camas Prairie Railroad (CSP), freight

Shortline and terminal railways

 * City of Boise Railroad (COB), freight
 * Eastern Idaho Railroad (EIRR), freight
 * Frontier Rail (FTRX), freight
 * Idaho Northern & Pacific Railroad (INPR), freight
 * Spokane, Spangle & Palouse Railway (SSP), freight

Defunct railways
Years shown here refer to the period in which a given company operated in Idaho; they may have existed elsewhere before or after these years.