Ill. Admin. Code tit. 20, § 2602.190
a) Scope
Procedures for receiving and sending mail must protect the youth's personal rights and provide for reasonable security practices consistent with the function of a detention facility. A youth shall be allowed to correspond with anyone if the correspondence does not violate any State or federal law, except a youth shall not be allowed to correspond with the victims of the youth's current or any previous offense unless the victim has given consent in writing.
b) Incoming Mail
3) Incoming letters containing contraband shall be held for further inspection and disposition by the superintendent.
Youth shall be permitted to receive an unlimited number of letters.
c) Outgoing Mail
Each youth shall be permitted to send, at personal expense, an unlimited number of letters.
d) Outgoing Privileged Mail
Outgoing letters from youth to persons or organizations listed in this subsection (d) are privileged communications and may be sealed by the youth prior to submission for mailing. Letters shall not be opened by the detention staff before mailing and shall be dispatched promptly.
e) Incoming Privileged Mail
Incoming mail from persons or organizations identified in the preceding standard may be opened only for verifying the addressee and the addressor, and to ascertain that nothing other than legal and/or official matter is enclosed. Mail opening must be in the presence of the youth.
f) Disciplinary Denial
Youth shall not be denied mail rights for disciplinary purposes; however, a serious violation of mail regulations may result in close scrutiny of mail.
g) Release, Transfer or Discharge
A released, transferred or discharged youth shall be permitted to take all personal mail.