Teton is a city in Fremont County, Idaho, United States. The population was 735 at the 2010 census. It is part of the Rexburg, Idaho Micropol…Teton is a city in Fremont County, Idaho, United States. The population was 735 at the 2010 census. It is part of the Rexburg, Idaho Micropolitan Statistical Area. Teton is located at 43°53′16″N 111°40′9″W / 43.88778°N 111.66917°W.