The Sex Offender Registration Act requires all persons who are considered sex offenders and under obligation to register to do so whenever they reside, permanently or temporarily, for 3 days or longer. The registration must be with either the Sheriff or the City Police department where the residence is located.
The Act is found at:
http://www.ilga.gov/legislation/ilcs/ilcs3.asp?ActID=2009&ChapAct=730%26nbsp%3BILCS%26nbsp%3B150%2F&ChapterID=55&ChapterName=CORRECTIONS&ActName=Sex+Offender+Registration+Act%2E
