The 47-acre farm is dotted with greenhouses that emit the pungent smell of thousands of marijuana plants and warehouses where farmworkers who spent their careers tending to raspberry plants now sit in rows delicately trimming the leaves from harvested cannabis buds. When the last greenhouses are built here next year, the facility will be one of the largest legal marijuana farms in the world.

Harborside and other farms like it are a sign of a new chapter for America’s cannabis industry, in which marijuana is grown openly, like any other crop. Despite the federal ban on marijuana, leaders of the industry are taking a Manifest Destiny view, believing it is only a matter of time for pot to become as widely accepted as alcohol across the country.

California, with its ideal climate and vast market, is at the vanguard of the movement to normalize the drug and produce it cheaply and in abundance.

“California is destined to do with cannabis what we’ve done with every other fruit and vegetable,” Mr. DeAngelo said. “And that’s take half of the national market.”

The move to mass-scale farming is occurring just as some members of the Trump administration are advocating a revival of the war on drugs, including marijuana, which is now legal in some form or another in about 30 states. The federal ban precludes growers of California cannabis from legally shipping out of state, although tons of it seeps out anyway.