Allerton is a city in Wayne County, Iowa. The population was 430 at the time of the 2020 census. According to the United States Census Bur…Allerton is a city in Wayne County, Iowa. The population was 430 at the time of the 2020 census. According to the United States Census Bureau, the city has a total area of 1.14 square miles, all land. Allerton reservoir and Bob White State Park are located approximately three miles west of Allerton.