Assumption is a city in Christian County, Illinois, United States.

[5] Assumption lays claim to the deepest coal mine (abandoned in the 1930s) in the state at over 1000' below the surface.

In May 2017, news reached Assumption of the recovery of the remains of United States Air Force Captain Joseph S. Smith, a pilot shot down over Cambodia in 1971 during the Vietnam War.

A large portion of the community turned out for his repatriation and interment in July 2017.

According to the 2020 census, Assumption has a total area of 0.88 square miles (2.28 km2), all land.

Since 1992, Assumption has been served by the Central A&M School District,[9] which also includes the village of Moweaqua, as well as the nearby rural areas.

Assumption is also home to Kemmerer Village, a private Presbyterian childcare agency, named for donor Philip Kemmerer who willed 400 acres (1.6 km2) to "the orphans and friendless poor of all denominations" in 1884.