(a) Service of process upon an unknown occupant may be had by delivering a copy of the summons and complaint naming "unknown occupants" to the tenant or any unknown occupant or person of the age of 13 or upwards occupying the premises.
9-107.5.Notice to unknown occupants.
Article IX. Eviction · Part 1. In General · Last amended 2018 · Last verified July 20, 2026
In one sentenceSection 9-107.5 lets a landlord serve and evict occupants whose identities aren't known, giving unnamed people found in possession 7 days to file a written claim to the premises before the sheriff removes them.
Full Text of 735 ILCS 5/9-107.5
(b) If unknown occupants are not named in the initial summons and complaint and an eviction order in favor of the plaintiff is entered, but the order does not include unknown occupants and the sheriff determines when executing the eviction order that persons not included in the order are in possession of the premises, then the sheriff shall leave with a person of the age of 13 years or upwards occupying the premises, a copy of the order, or if no one is present in the premises to accept the order or refuses to accept the order, then by posting a copy of the order on the premises. In addition to leaving a copy of the order or posting of the order, the sheriff shall also leave or post a notice addressed to "unknown occupants" that states unless any unknown occupants file a written petition with the clerk that sets forth the unknown occupant's legal claim for possession within 7 days of the date the notice is posted or left with any unknown occupant, the unknown occupants shall be evicted from the premises. If any unknown occupants file such a petition, a hearing on the merits of the unknown occupant's petition shall be held by the court within 7 days of the filing of the petition with the clerk. The unknown occupants shall have the burden of proof in establishing a legal right to continued possession.
(c) The plaintiff may obtain an eviction order only and not for rent as to any unknown occupants.
(d) Nothing in this Section may be construed so as to vest any rights to persons who are criminal trespassers, nor may this Section be construed in any way that interferes with the ability of law enforcement officials removing persons or property from the premises when there is a criminal trespass.
Plain-English Summary
Initial service on unknown occupants can be accomplished by delivering a copy of the summons and complaint, naming 'unknown occupants,' to the tenant, to any unknown occupant, or to anyone 13 or older occupying the premises.
The section also covers people the sheriff finds in possession later, who weren't named in the original order. The sheriff leaves, or posts, a copy of the order plus a notice addressed to 'unknown occupants,' warning that unless they file a written petition with the clerk asserting a legal claim to possession within 7 days, they'll be evicted. Filing that petition triggers a hearing within 7 days, and the occupant carries the burden of proving a legal right to stay.
The remedy against unknown occupants is narrower than against named defendants: a plaintiff can only get an eviction order against them, never a rent judgment. And nothing in the section protects criminal trespassers or interferes with law enforcement removing them.
Frequently Asked Questions
Can a landlord evict people living in a unit whose names are unknown?
Yes, by naming and serving 'unknown occupants' under this section.
What happens if the sheriff finds people in the unit who weren't named in the eviction order?
The sheriff leaves or posts a copy of the order plus a notice giving them 7 days to file a written petition asserting a legal claim to possession, or be evicted.
What happens if an unknown occupant files that petition?
The court must hold a hearing within 7 days of the filing, and the occupant carries the burden of proving a legal right to continued possession.
Can a landlord get a money judgment against an unknown occupant?
No, only an eviction order, not a judgment for rent.
Does this section protect a criminal trespasser from removal?
No, it doesn't vest any rights in criminal trespassers or interfere with law enforcement removing them.
Amendment History
(Source: P.A. 100-173, eff. 1-1-18.)
Source & verification. Section text and amendment history are
reproduced verbatim from the Illinois Compiled Statutes, published by the
Illinois Compiled Statutes, Illinois General Assembly / Legislative Reference Bureau. Last verified July 20, 2026.
· Official source
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