Madison county is located in central Ohio just southwest of Columbus and utilizes London as the count seat. The county population on July 1, 1999, was 41,348, an increase of 4,270 over the 1990 census.

This is a largely rural county situated between the more metropolitan areas of Franklin County and Montgomery County. Natural features include Madison Lake just southeast of the county seat, Deer Creek which feeds the lake and flowing in a southeasterly direction through the southern two-thirds of the county and Little Darby Creek to the north.