Buhl is a city located on the old Oregon Trail in the western half of Twin Falls County, Idaho. The population was 4,122 at the time of the 201…Buhl is a city located on the old Oregon Trail in the western half of Twin Falls County, Idaho. The population was 4,122 at the time of the 2010 census, up from 3,985 in 2000. It is part of the Twin Falls, Idaho metropolitan area.