Fremont is a city in Mahaska County, Iowa, United States. The population was 708 at the time of the 2020 census. In 1871, Fremont stretched f…Fremont is a city in Mahaska County, Iowa, United States. The population was 708 at the time of the 2020 census. In 1871, Fremont stretched for 8 blocks, 1/2 mile along Main Street, with at least one house on every block on the north side of the street and a few houses on Washington Street, one block north. There was a Baptist church, a hotel, three stores, a barber shop and a school. The town also had a physician, a blacksmith and a shoemaker.