Manlius is a village in Bureau County, Illinois, United States. The population was 355 at the 2000 census. It is part of the Ottawa–Streator Micropolitan Statistical Area.
According to the United States Census Bureau, the village has a total area of 0.3 square miles (0.8 km²), all of it land.
As of the census of 2000, there were 355 people, 149 households, and 96 families residing in the village. The population density was 1,158.7 people per square mile (442.1/km²). There were 165 housing units at an average density of 538.6 per square mile (205.5/km²). The racial makeup of the village was 98.59% White, 0.28% African American, 0.85% Native American, 0.28% from other races. Hispanic or Latino of any race were 3.66% of the population.