625 ILCS 5/1-172: Residence district.

The territory contiguous to and including a highway not comprising a business district when the property on such highway for a distance of 300 feet or more is in the main improved with residences or residences and buildings in use for business.

For purposes of establishing maximum speed limits, a residence district shall be at least a quarter of a mile long with residences or residences and buildings in use for businesses spaced no more than 500 feet apart.