Marshall 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 13,180 people, with a population density of about 34.15 persons per square mile.
The county spans a total land area of 386.00 square miles (1,000.00 square kilometers). The administrative center and county seat is Lacon, which often serves as a hub for local governance and services. The largest city within the county by population is Henry.
Geographically, Marshall County experiences varied elevations, with its highest point at Varna 729 ft and its lowest point at Hopewell 476 ft. The region operates in the UTC-6.