It happened around 9:15 p.m. Sunday night near Weston in Yates Township.
Pronounced dead on scene are 52-year-old Eldon Kaeb and his wife 45-year-old Stephanie Kaeb.
Authorities say the couple was driving northbound on County Rd. 3360 East when it collided with a semi tractor trailer traveling westbound on Illinois Rt. 24.
They had left a family gathering and were headed to Wisconsin when the crash occurred.
Emergency crews arrived and found the couple trapped inside their vehicle without obvious signs of life.
The cause of the crash is under investigation.
Meanwhile, the couple leaves behind nine children ranging in age from around six to early 20's and a family farm.
The children are staying with family.
Autopsies are scheduled for Tuesday, October 9.