About This Place
Assumption is a city in Christian County, Illinois, United States. The population was 1,168 at the 2010 census.
Assumption is located at 39°31′10″N 89°02′57″W / 39.519545°N 89.049129°W / 39.519545; -89.049129.
According to the United States Census Bureau, the city has a total area of 0.9 square miles (2.3 km²), all of it land.