New Hampton is a city in, and the county seat of, Chickasaw County, Iowa, United States. The population was 3,494 at the time of the 202…New Hampton is a city in, and the county seat of, Chickasaw County, Iowa, United States. The population was 3,494 at the time of the 2020 census. New Hampton was founded c. 1855. It is named after New Hampton, New Hampshire, the native town of one of its founders.