A staggering 10 million people have entered the U.S. illegally since inauguration day in what is an economic ticking time bomb, says author Todd Bensman.

“We’ve never seen anything like it,” he told the Herald. “It’s the biggest and baddest migration in the history of the United States and maybe the world.”

Local schools, area hospitals — “any quality of life metric” — will be overwhelmed due to this migration, he said. The courts, police, prisons and the “downward pressure on wages” will also change society drastically.

“There’s a price tag to all this that Americans are finally waking up to,” he said. “There will be political change and you’ll see it in the black and Latino neighborhoods, too.”

Bensman, author of the book “Overrun: How Joe Biden unleashed the greatest border crisis in U.S. history,” is set to speak Tuesday at the West Roxbury Elks Hall in a free session on the migrant crisis. His appearance is sponsored by the group,  Bostonians Against Sanctuary Cities.

It comes at Gov. Maura Healey’s administration is scrambling to house newly arrived migrants in a Roxbury rec center, a Fort Point office building and hotels and motels across the state. Speculation is running rampant about where the governor’s staff will house migrants next.

The Bay State emergency shelter system is maxed out at the 7,500 family limit Healey unilaterally imposed last year and there’s no indication of aid coming from Washington any time soon.

Some lawmakers are considering a supplemental budget that taps $873 million in surplus dollars from the pandemic to plug a $224 million shelter budget gap this fiscal year and pay down costs in the next, when spending is expected to approach $1 billion.

Healey also pointed to her administration’s work to speed up work permit approvals for newly arrived migrants to move them out of shelters. There’s the “downward pressure on wages” playing out already.

Bensman warns these “fiscal burdens” are just the start and will soon “be mammoth.”

He devotes a chapter in his book to the overwhelming number of children now in the U.S. and the pressure just now building on school systems to teach them in a language that’s foreign to them.

All the while the cartels, he adds, cash in on this migration of misery that’s also a threat to the nation’s security.

The Department of Homeland Security has let in at least 44,000 Chinese nationals who illegally crossed the southwest border from the time President Biden took office through January of this year, most of them flying first into Ecuador on cheap tourist visas available for a few bucks online, Bensman first wrote in the New York Post.

He told the Herald that China is one of 170 countries where illegal immigrants come from as they cross the southern border — with “virtually all of them getting right in.” Bensman’s book tells of the porous border.

He said many of the Chinese crosser are “economic migrants” looking for the American dream. But others are spies sent in by China — “it’s their thing,” he said.

And the border crossings just keep happening.

“There’s no country I haven’t seen represented on the border,” he added. “We need to stop it at its source.”

The dual tragedy in the migrant crisis, Bensman writes at the end of his book, is America and the border crossers both suffer: “Only when the end-runs are pinched closed and the remaining sensible laws enforced with universal consistency will the vast numbers of foreign nationals finally stop coming — and dying on the way.”

Migrants walk along the highway through Arriaga, Chiapas state in southern Mexico in January during their journey north toward the U.S. border. (AP Photo/Edgar H. Clemente, File)