735 ILCS 5/13-110
Whenever a person having color of title, made in good faith, to vacant and unoccupied land, pays all taxes legally assessed thereon for 7 successive years, he or she shall be deemed and adjudged to be the legal owner of such vacant and unoccupied land, to the extent and according to the purport of his or her paper title. All persons holding under such taxpayer, by purchase, legacy or descent, before such 7 years expired, and who continue to pay the taxes, as above set out, so as to complete the payment of taxes for the term, are entitled to the benefit of this Section. However, if any person, having a better paper title to such vacant and unoccupied land, during the term of 7 years, pays the taxes assessed on such land for any one or more years of the term of 7 years, then such taxpayer, his or her heirs, legatees or assigns, shall not be entitled to the benefit of this Section.
735 ILCS 5/13-110