There was a total of around $600,000 of farmsand rural real estate for sale in Putnam County recently on Land.com. The total acreage of all Putnam County farms, rural land, hunting land and other land for sale was nearly 1,000 acres. Putnam County ranks 90th out of 102 counties in Illinois for the total number of acres of land currently advertised for sale. Putnam featured the most land for sale. Putnam County is Illinois's 102nd largest county (172 square miles). It's located in the Western Illinois region of Illinois.