The Cook County medical examiner said 10-year-old Ombre Mangram died from her injuries Monday.
She was one of two kids in a pickup truck that crashed into a frozen creek last Thursday.
Deputies responded at about 11:23 p.m. to the area of 3700 E. Route 17 after getting an automated crash alert from an iPhone.
The other child was in critical condition after the crash, as well.
The driver, Phyllis Moses, 58, was also taken to a hospital and subsequently arrested for DUI, the Kankakee County Sheriff's Office said.