Operation Smack Talk, an 11-month investigation in Tucson, yielded 123 pounds of high-grade heroin, the Drug Enforcement Agency announced.
Seven people were arrested in the sting.
The high-grade heroin came from Mexico, was stashed at a drop house in Tucson by members of the Sinaloa cartel, and then distributed to Colorado, Nevada and Oregon, said DEA Spokeswoman Ramona Sanchez.
Six of the seven people arrested were United States citizens.
"You’re talking about the people the drug cartels rely upon to store this much heroin and to transport it across the border," Sanchez said. "They have a lot of responsibility."
The DEA said the drugs are worth $7.5 million on the street. Agents also seized $300,000 in cash and seven vehicles.