(720 ILCS 5/21-3) (from Ch. 38, par. 21-3)
    Sec. 21-3. Criminal trespass to real property.
    (a) A person commits criminal trespass to real property when he or she:
        (1) knowingly and without lawful authority enters or
    
remains within or on a building;
        (2) enters upon the land of another, after receiving,
    
prior to the entry, notice from the owner or occupant that the entry is forbidden;
        (3) remains upon the land of another, after receiving
    
notice from the owner or occupant to depart;
        (3.5) presents false documents or falsely represents
    
his or her identity orally to the owner or occupant of a building or land in order to obtain permission from the owner or occupant to enter or remain in the building or on the land;
        (3.7) intentionally removes a notice posted on
    
residential real estate as required by subsection (l) of Section 15-1505.8 of Article XV of the Code of Civil Procedure before the date and time set forth in the notice; or
        (4) enters a field used or capable of being used for
    
growing crops, an enclosed area containing livestock, an agricultural building containing livestock, or an orchard in or on a motor vehicle (including an off-road vehicle, motorcycle, moped, or any other powered two-wheel vehicle) after receiving, prior to the entry, notice from the owner or occupant that the entry is forbidden or remains upon or in the area after receiving notice from the owner or occupant to depart.
    For purposes of item (1) of this subsection, this Section shall not apply to being in a building which is open to the public while the building is open to the public during its normal hours of operation; nor shall this Section apply to a person who enters a public building under the reasonable belief that the building is still open to the public.
    (b) A person has received notice from the owner or occupant within the meaning of Subsection (a) if he or she has been notified personally, either orally or in writing including a valid court order as defined by subsection (7) of Section 112A-3 of the Code of Criminal Procedure of 1963 granting remedy (2) of subsection (b) of Section 112A-14 of that Code, or if a printed or written notice forbidding such entry has been conspicuously posted or exhibited at the main entrance to the land or the forbidden part thereof.
    (b-5) Subject to the provisions of subsection (b-10), as an alternative to the posting of real property as set forth in subsection (b), the owner or lessee of any real property may post the property by placing identifying purple marks on trees or posts around the area to be posted. Each purple mark shall be:
        (1) A vertical line of at least 8 inches in length
    
and the bottom of the mark shall be no less than 3 feet nor more than 5 feet high. Such marks shall be placed no more than 100 feet apart and shall be readily visible to any person approaching the property; or
        (2) A post capped or otherwise marked on at least its
    
top 2 inches. The bottom of the cap or mark shall be not less than 3 feet but not more than 5 feet 6 inches high. Posts so marked shall be placed not more than 36 feet apart and shall be readily visible to any person approaching the property. Prior to applying a cap or mark which is visible from both sides of a fence shared by different property owners or lessees, all such owners or lessees shall concur in the decision to post their own property.
    Nothing in this subsection (b-5) shall be construed to authorize the owner or lessee of any real property to place any purple marks on any tree or post or to install any post or fence if doing so would violate any applicable law, rule, ordinance, order, covenant, bylaw, declaration, regulation, restriction, contract, or instrument.
    (b-10) Any owner or lessee who marks his or her real property using the method described in subsection (b-5) must also provide notice as described in subsection (b) of this Section. The public of this State shall be informed of the provisions of subsection (b-5) of this Section by the Illinois Department of Agriculture and the Illinois Department of Natural Resources. These Departments shall conduct an information campaign for the general public concerning the interpretation and implementation of subsection (b-5). The information shall inform the public about the marking requirements and the applicability of subsection (b-5) including information regarding the size requirements of the markings as well as the manner in which the markings shall be displayed. The Departments shall also include information regarding the requirement that, until the date this subsection becomes inoperative, any owner or lessee who chooses to mark his or her property using paint, must also comply with one of the notice requirements listed in subsection (b). The Departments may prepare a brochure or may disseminate the information through agency websites. Non-governmental organizations including, but not limited to, the Illinois Forestry Association, Illinois Tree Farm and the Walnut Council may help to disseminate the information regarding the requirements and applicability of subsection (b-5) based on materials provided by the Departments. This subsection (b-10) is inoperative on and after January 1, 2013.
    (b-15) Subsections (b-5) and (b-10) do not apply to real property located in a municipality of over 2,000,000 inhabitants.
    (c) This Section does not apply to any person, whether a migrant worker or otherwise, living on the land with permission of the owner or of his or her agent having apparent authority to hire workers on this land and assign them living quarters or a place of accommodations for living thereon, nor to anyone living on the land at the request of, or by occupancy, leasing or other agreement or arrangement with the owner or his or her agent, nor to anyone invited by the migrant worker or other person so living on the land to visit him or her at the place he is so living upon the land.
    (d) A person shall be exempt from prosecution under this Section if he or she beautifies unoccupied and abandoned residential and industrial properties located within any municipality. For the purpose of this subsection, "unoccupied and abandoned residential and industrial property" means any real estate (1) in which the taxes have not been paid for a period of at least 2 years; and (2) which has been left unoccupied and abandoned for a period of at least one year; and "beautifies" means to landscape, clean up litter, or to repair dilapidated conditions on or to board up windows and doors.
    (e) No person shall be liable in any civil action for money damages to the owner of unoccupied and abandoned residential and industrial property which that person beautifies pursuant to subsection (d) of this Section.
    (e-5) Mortgagee or agent of the mortgagee exceptions.
        (1) A mortgagee or agent of the mortgagee shall be
    
exempt from prosecution for criminal trespass for entering, securing, or maintaining an abandoned residential property.
        (2) No mortgagee or agent of the mortgagee shall be
    
liable to the mortgagor or other owner of an abandoned residential property in any civil action for negligence or civil trespass in connection with entering, securing, or maintaining the abandoned residential property.
        (3) For the purpose of this subsection (e-5) only,
    
"abandoned residential property" means mortgaged real estate that the mortgagee or agent of the mortgagee determines in good faith meets the definition of abandoned residential property set forth in Section 15-1200.5 of Article XV of the Code of Civil Procedure.
    (f) This Section does not prohibit a person from entering a building or upon the land of another for emergency purposes. For purposes of this subsection (f), "emergency" means a condition or circumstance in which an individual is or is reasonably believed by the person to be in imminent danger of serious bodily harm or in which property is or is reasonably believed to be in imminent danger of damage or destruction.
    (g) Paragraph (3.5) of subsection (a) does not apply to a peace officer or other official of a unit of government who enters a building or land in the performance of his or her official duties.
    (h) Sentence. A violation of subdivision (a)(1), (a)(2), (a)(3), or (a)(3.5) is a Class B misdemeanor. A violation of subdivision (a)(4) is a Class A misdemeanor.
    (i) Civil liability. A person may be liable in any civil action for money damages to the owner of the land he or she entered upon with a motor vehicle as prohibited under paragraph (4) of subsection (a) of this Section. A person may also be liable to the owner for court costs and reasonable attorney's fees. The measure of damages shall be: (i) the actual damages, but not less than $250, if the vehicle is operated in a nature preserve or registered area as defined in Sections 3.11 and 3.14 of the Illinois Natural Areas Preservation Act; (ii) twice the actual damages if the owner has previously notified the person to cease trespassing; or (iii) in any other case, the actual damages, but not less than $50. If the person operating the vehicle is under the age of 16, the owner of the vehicle and the parent or legal guardian of the minor are jointly and severally liable. For the purposes of this subsection (i):
        "Land" includes, but is not limited to, land used for
    
crop land, fallow land, orchard, pasture, feed lot, timber land, prairie land, mine spoil nature preserves and registered areas. "Land" does not include driveways or private roadways upon which the owner allows the public to drive.
        "Owner" means the person who has the right to
    
possession of the land, including the owner, operator or tenant.
        "Vehicle" has the same meaning as provided under
    
Section 1-217 of the Illinois Vehicle Code.
    (j) This Section does not apply to the following persons while serving process:
        (1) a person authorized to serve process under
    
Section 2-202 of the Code of Civil Procedure; or
        (2) a special process server appointed by the circuit
    
court.
(Source: P.A. 97-184, eff. 7-22-11; 97-477, eff. 8-22-11; 97-813, eff. 7-13-12; 97-1108, eff. 1-1-13; 97-1164, eff. 6-1-13.)