Fairmont City is a village in St. Clair and Madison counties, Illinois, United States. The population was 2,265 at the 2020 census, down from 2,635 in 2010. In the 1990s Fairmont City's Hispanic population doubled, and as of 2020, over 79% of the population was of Hispanic descent. Geography Fairmont City is located in northwestern St. Clair County at (38.651200, -90.099788). A small part of the village extends north into southwestern Madison County. The community is bordered to the northwest by Brooklyn, to the north by Madison, to the northeast by Pontoon Beach, to the east by Collinsville, to the southeast by Caseyville, to the south by Washington Park, and to the southwest by East St. Louis. The village limits extend west from the main portion of Fairmont City to touch the Mississippi River directly across from St. Louis. According to the U.S. Census Bureau, Fairmont City has a total area of , of which are land and , or 5.22%, are water. Fairmont City is built atop portions of the Cahokia Mounds, a UNESCO World Heritage Site. Sam Chucalo Mound, one of the mounds, is in the western part of the village. Other mounds are in the eastern part of the village within Cahokia Mounds State Historic Site. In April 2016, the US Environmental Protection Agency added the Old American Zinc Fairmont City site to the National Priorities List following the Illinois EPA discovering high levels of lead, arsenic, cadmium and zinc in soil samples. Collected soil samples from properties and alleyways showed residue of arsenic, cadmium and zinc. Fairmont City is east of the Gateway Arch of St. Louis. Sunset often provides picturesque views of the arch and St. Louis' skyline. Collinsville Road runs the length of the village. This route once contained an accumulation of vintage, in situ roadside Americana advertising signage, most of which has not been removed or destroyed over time. National City, a former company town to the west of Fairmont City, dissolved in 1997 and was annexed by Fairmont City. Demographics As of the census of 2000, there were 2,436 people, 871 households, and 580 families residing in the village. The population density was . There were 939 housing units at an average density of . The racial makeup of the village was 41.54% White, 1.23% African American, 0.94% Native American, 0.08% Asian, 27.50% from other races, and 3.69% from two or more