Maeystown is a village in Monroe County, Illinois, United States. The population was 150 at the 2020 census. Maeystown is located southwest of the center of Monroe County at 38°13′32″N 90°14′1″W / 38.22556°N 90.23361°W. It is 9 miles southwest of Waterloo, the county seat. It sits in the valley of Maeystown Creek, which flows into the floodplain of the …Maeystown is a village in Monroe County, Illinois, United States. The population was 150 at the 2020 census. Maeystown is located southwest of the center of Monroe County at 38°13′32″N 90°14′1″W / 38.22556°N 90.23361°W. It is 9 miles southwest of Waterloo, the county seat. It sits in the valley of Maeystown Creek, which flows into the floodplain of the Mississippi River 2 miles to the southwest.