For the motion picture, see Twin Falls Idaho (film) Twin Falls is the county seat and largest city of Twin Falls County, Idaho, United States. The population was 34,469 at the 2000 census; a 2006 estimate found 40,380 people. Twin Falls is the largest city of Idaho's Magic Valley region and the seventh largest in the state. As the largest city in a 100-mile (166-kilometer) radius, Twin Falls serves as a regional commercial center for both south-central Idaho and northeastern Nevada. Twin Falls is the principal city of the Twin Falls, ID Micropolitan Statistical Area - the state's largest - which officially includes Jerome and Twin Falls Counties. The resort community of Jackpot, Nevada, in Elko County is unofficially considered part of the greater Twin Falls area.