First responders answered to a call last Friday in the 1600-Block of North Blue Bell Bend Road in rural Watseka, sheriff's office said.
A three-week-old baby was not breathing, and was rushed to Lurie Children's Hospital in Chicago.
Baby Jace died on Monday at the hospital, sheriff's office said.
Jason Ruiz, 22, was taken into custody in Chicago on Thursday.
He was charged with first-degree murder and aggravated battery.
No other information was available.