Hillsboro is located in south central Illinois in Montgomery County (of which it is the county seat) northeast of St Louis along Highway 127 near Lake Lou Yeager and Glenn Shoals Lake to the north and the Coffeen Lake SFWA to the south. The population estimate for July 1, 1998 was 4,058, a decrease of 342 since 1990.
As a point of community pride, Hillsboro is regarded as the "Bluegrass Capital of Illinois."
