Jefferson County is in Southern Illinois. Of the 102 counties in the Prairie State, Jefferson County is 41st in terms of its size (583 square miles). The most common type of land for sale by combined acreage in Jefferson County is residential property. Browse all waterfront property for sale in Jefferson County on the Land Network to find the marina, lakefront and other recreational property that meets your needs, from waterside land perfect as a retirement investment to existing residential waterfront land and property for hunting, fishing and other outdoor-recreation pursuits!