Girardeau is a village located in Alexander County, in the state of Illinois (IL), United States. Nestled in the East North Central division of the Midwest region, it covers an area of 2.0 square miles (5.0 km²) and sits at an elevation of 340 ft. With a population of approximately 437 residents, Girardeau offers a peaceful, rural atmosphere.
The town's population is composed of about 48.74% males and 51.26% females, and it has a population density of 221.83 people per square mile (85.65/km²). Girardeau lies at a latitude of 37.3 and a longitude of -89.5, operating in the UTC-6.
Locals reflect a blend of American ancestry, with roots primarily in United States (24.3%), followed by English (3.7%), German (16.7%), and Scotch-Irish (0%) heritage. The town is identified by the ZIP code 62957.