More than 17 pounds of cocaine worth nearly $800,000 was seized by Illinois State Police in southwestern Illinois, they said.
The bust happened Wednesday on Interstate 70 near Pierron, about 40 miles northeast of St. Louis, authorities said.
The drugs were reportedly found during a traffic stop. State police say a trooper stopped a white SUV for speeding and following too closely. The officer called in a police dog, which alerted the trooper to the presence of an illegal substance.
A search of the SUV found seven cellophane-wrapped bundles of cocaine, authorities said.
State Police Captain Brad Parsons says troopers try to look beyond a basic traffic stop to make sure there aren't other crimes going on.
Both the SUV's driver and passenger are being held at the Madison County Jail on drug charges.