Ill. Admin. Code tit. 17, § 675.50
a) Successful hunters must register their harvest by 10:00 p.m. on the same calendar day the deer was taken by calling the toll-free telephone check-in system at 1-866-ILCHECK or by accessing the on-line check-in system at www.dnr.illinois.gov. If a hunter is not able to locate a harvested deer in sufficient time to enable reporting the harvest by 10:00 p.m., the hunter must immediately report the harvest upon retrieving it. They will be provided with a confirmation number to verify that they checked in their harvest. This number must be written by the hunter on the harvest tag (leg tag). If the condition of the tag precludes writing on the tag in the appropriate space (i.e., bloody, etc.), the confirmation number shall be written elsewhere on the tag or onto a piece of paper and attached to the deer along with the temporary harvest tag. The deer must remain whole (or field dressed) until it has been checked in. In instances in which deer are checked in while the hunter is still afield, the deer may not be dismembered while afield beyond quartering the animal. If quartered, all parts of the carcass (except the entrails removed during field dressing) must be transported together and evidence of sex must remain naturally attached to one quarter. Evidence of sex is:
(Source: Amended at 46 Ill. Reg. 18729, effective November 2, 2022)