Federal drug officials have helped break up an upstate drug ring and seized more than 6,000 pounds of marijuana worth nearly $20 million, they announced on Wednesday.

The drug ring, based in Sullivan County, was distributing marijuana across the Northeast, including New York City. The authorities said the operation was spread across a number of homes in Mamakating, a town of 11,000 about an hour and a half from Manhattan.

On Tuesday night, federal drug enforcement agents and Sullivan County Sheriff’s officers raided the homes, seized more than 6,300 marijuana plants and arrested 16 people, Preet Bharara, the United States attorney for the Southern District of New York, said in court documents.

The federal Drug Enforcement Administration called it the largest breakup of an indoor marijuana-growing operation in New York’s history.