Massac County is a county located in the U.S. state of Illinois. As of the most recent data available, the county has a population of approximately 15,161 people, with a population density of about 63.44 persons per square mile.
The county spans a total land area of 239.00 square miles (619.00 square kilometers). The administrative center and county seat is Metropolis, which often serves as a hub for local governance and services. The largest city within the county by population is Metropolis.
Geographically, Massac County experiences varied elevations, with its highest point at Metropolis 350 ft and its lowest point at Brookport 340 ft. The region operates in the UTC-6.