In a partition lawsuit, all of the parties who have an interest must be sued. See 735 ILCS 5/17-103.  The suit must be filed in the county where the property is located. See 735 ILCS 5/17-101.  When jurisdiction over everyone is established, the judge appoints a commissioner to investigate the property. See 735 ILCS 5/17-106.  For things like farm land, …