PHOENIX — Law enforcement officials on Monday announced the breakup of a large drug-smuggling ring that used lookouts on hilltops in southern Arizona to move huge quantities of marijuana and other drugs across the Mexican border to users throughout the United States.

Over the last month and a half, federal, state and local officials have arrested 76 people, from organizational bosses to stash-house guards to those who transported the drugs in backpacks and in vehicles, the authorities said. All were linked to the Sinaloa cartel run by Joaquín Guzmán, Mexico’s richest and most wanted outlaw, who goes by the nickname El Chapo, officials said.

Speaking at a news conference on Monday, Arizona officials estimated that the ring had been in operation for at least five years and had generated more than $2 billion in profits by smuggling more than three million pounds of marijuana, 20,000 pounds of cocaine and 10,000 pounds of heroin into the United States. Such large smuggling rings usually use tractor-trailers to get their contraband across, the authorities said, but this operation relied mostly on migrants on foot straining under their loads.

The authorities acknowledged that the huge smuggling ring operated under their noses, in rugged terrain that is difficult to patrol. The drugs would be carried across the border in relatively small quantities and then transported north to a network of stash houses in the Phoenix area. From there, the contraband would be sold to distributors nationwide.