Indiana State Police said troopers responded to the crash on eastbound Interstate 80/94 near Kennedy Avenue in the morning hours.
Video from the scene near Hammond appears to show a semi that had crashed into a car hauler carrying several vehicles.
ISP said a medical helicopter transported the critically injured person to a hospital.
Both eastbound and westbound lanes were initially closed. ISP said all westbound lanes have reopened, and eastbound traffic is getting by through one lane.
What caused the crash was not immediately clear.
Authorities did not immediately provide additional information.