Ashton - is a city in Fremont County, Idaho, United States. The population was 1,127 at the 2010 census, and it is part of the RexburgMicropolitan Statistical Area. The district is noted for seed potato production and bills itself as the world's largest seed potato growing area. The City of Ashton is fantastic place to live! One of the most wonderful natural resources of the City of Ashton is certainly the incredible view that can be had of the Teton Mountains rising out of the farmland to the northeast.