Thayer is a village located in Sangamon 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 0.6 square miles (2.0 km²) and sits at an elevation of 645 ft. With a population of approximately 750 residents, Thayer offers a peaceful, rural atmosphere.
The town's population is composed of about 51.2% males and 48.8% females, and it has a population density of 250.00 people per square mile (482.63/km²). Thayer lies at a latitude of 39.54 and a longitude of -89.76, operating in the UTC-6.
Locals reflect a blend of American ancestry, with roots primarily in United States (14.4%), followed by English (17.7%), German (18.7%), and Scotch-Irish (0%) heritage. The town is identified by the ZIP code 62689.