Greenup is a village in Cumberland County, Illinois, along the Embarras River. The population was 1,494 at the 2005 census. It is part of the Charleston–Mattoon Micropolitan Statistical Area. Greenup received its name from National Road surveyor, William C. Greenup, who plotted the town in 1834. William C. Greenup was one of the supervisors hired to oversee construction of the National Road in Illinois, surveying the original alignment from Marshall to Vandalia during the 1830s. The town of Greenup served as the Cumberland County seat from 1843 to 1857.