Mechanicsburg is a village in Sangamon County, Illinois, United States. The population was 456 at the 2000 census. It is part of the Springfield, Illinois Metropolitan Statistical Area.Mechanicsburg is located at 39°48′34″N 89°23′51″W / 39.80944°N 89.39750°W / 39.80944; -89.39750.According to the 2010 census, Mechanicsburg has a total area of 1.07 square miles, all land.As of the census of 2000, there were 456 people, 172 households, and 121 families residing in the village. The population density was 1,203.2 people per square mile. There were 198 housing units at an average density of 522.4 per square mile. The racial makeup of the village was 97.15% White, 0.88% African American, 0.66% Asian, 0.88% from other races, and 0.44% from two or more races. Hispanic or Latino of any race were 0.22% of the population.There were 172 households out of which 39.0% had children under the age of 18 living with them, 52.9% were married couples living together, 12.