Police responded to the crash on Route 68, just west of Dundee Lane at 4:19 p.m., according to a Barrington Hills police release.
Sarah Yaple, 84, of St. Charles, and Oscar Arce, 24, of North Aurora, were both pronounced dead Thursday at St. Alexius Hospital in Hoffman Estates. Arce's passenger, Elroy Arce, 25, was being treated for injuries, according to police.
Witnesses stated a 2004 Nissan Maxima, driven by Arce, was eastbound on Route 68 when it crossed the solid yellow line and struck a westbound 2002 Buick LeSabre, driven by Yaple, head-on.
Alcohol was a contributing factor to the crash, the release said.
The accident is still under investigation.
The Sun-Times Media Wire contributed to this report.