Batavia is a city in Jefferson County, Iowa, United States. The population was 430 at the 2020 census. It was established in 1846. According t…Batavia is a city in Jefferson County, Iowa, United States. The population was 430 at the 2020 census. It was established in 1846. According to the United States Census Bureau, the city has a total area of 0.60 square miles, all land.