Indiana State Police troopers responded to the crash on northbound Interstate 65, north of 61st Avenue, just before 2 a.m. That's near Merrillville.
ISP said a 29-year-old woman was driving a silver 2022 Toyota southbound in the northbound lanes when she struck a 2016 Ford head-on in the far-left lane.
The Ford's driver was pronounced dead on the scene, ISP said. She has been identified as 20-year-old Rylee Hanson, of Hobart.
A female passenger in the Ford suffered serious injuries and was taken to St. Mary Medical Center for treatment, ISP said. Her age was not immediately known.
Local fire personnel extricated the Toyota's driver before she was airlifted to a hospital in Chicago, where she is in critical condition. Investigators believe she was impaired at the time of the crash.
I-65 was temporarily shut down in both directions. All lanes have since reopened.
No charges have been filed, ISP said, and the investigation is ongoing.
ISP asked anyone with footage of the crash or the vehicles prior to the crash to contact Trooper Somerville at 219-696-6242.