The change is evident in the once-moribund downtowns of northeastern Ohio cities as well as in the economic data for the state as a whole.

Ohio’s unemployment rate in July was 5.7 percent, well below the national average of 6.1 percent. That’s a sharp reversal of the situation four years ago, when unemployment in Ohio hit 10.6 percent, significantly above the country’s overall jobless rate at the time, as manufacturers here and elsewhere hemorrhaged jobs. In the Youngstown area, the jobless rate in July was 6.7 percent, compared with 13.3 percent in early 2010.

“Both Youngstown and Canton are places which experienced nothing but disinvestment for 40 years,” said Ned Hill, a professor of economic development at Cleveland State University. Now, “they’re not ghost towns anymore. You actually have to go into reverse to find a parking spot downtown.”

Youngstown and surrounding Mahoning County is hardly Silicon Valley or even Pittsburgh, which long ago bade farewell to its industrial past and sought out growth in new sectors like health care and education. Broad swaths of Youngstown look almost rural, the result of a decade-long campaign to tear down abandoned homes and factories, letting sites that were once eyesores return to nature.

And the new factories that have gone up — like Vallourec’s new complex, or a $13.2 million plant that Exterran opened in May 2013 to make oil and gas production equipment for local customers — employ only a fraction of the workers who once labored at Youngstown’s mills. Vallourec’s state-of-the-art pipe mill has about 350 workers; the old Youngstown Sheet & Tube plant that once stood on the site had a work force of 1,400 when it shut down in 1979.

But the improvement is undeniable, especially to those who grew up here. “It’s a night-and-day difference,” said Robert E. Roland, a Youngstown native who moved away when he was 18, and is now managing partner at one of Canton’s biggest law firms, Day Ketterer. “It was extremely depressed, and nobody was downtown except for people who were down and out.”