Twin Falls is the county seat and largest city of Twin Falls County, Idaho, United States. The city had a population of 51,807 as of the 2020 census. In the Magic Valley region, Twin Falls is the largest city in a 100-mile radius, and is the regional commercial center for south-central Idaho and northeastern Nevada. It is the principal city of the Twin Falls metropolitan statistical area, which officially includes the entirety of Twin Falls and Jerome Counties.