Wales, Wis. ? After struggling for years to treat young criminals in razor wire-ringed institutions, states across the country are quietly shuttering dozens of reformatories amid plunging juvenile arrests, softer treatment policies and bleak budgets.

In Ohio, the number of juvenile offenders has plummeted by nearly half over the last two years, pushing the state to close three facilities. California’s closures include a youth institution near Los Angeles that operated for nearly 115 years. And one in Texas will finally go quiet after getting its start as a World War II-era training base.

Some of the closed reformatories around the country will become adult prisons. Others are up for sale, like the one in Kansas that closed in 2008 saving the state $3.7 million.

The closures have juvenile advocates cheering.

“I can tell you it’s the best thing they can do,” said Aaron Kupchik, a University of Delaware criminologist. “Incarceration does nobody any good. You’re taking away most of their chance for normal development.”

Several factors have pushed states to close facilities. In stark contrast to the growing adult prison population, the number of juveniles in state lockups has dropped dramatically, partly because there are fewer juvenile arrests and more offenders in county-based treatment programs. States grappling with busted budgets can’t afford to operate facilities with so many empty beds.

State reformatories are typically reserved for serious criminals, such as sex offenders and other violent offenders. Unlike the punishment-oriented adult system, juvenile justice focuses on rehabilitation.

During the early 1990s, though, tough-on-crime legislators turned to the juvenile system. Nearly every state lowered the minimum age for kids to be tried as adults or increased the kind of crimes that land kids in the adult system.

But juvenile arrest rates dropped, falling 33 percent between 1997 and 2008, according to the latest U.S. Justice Department data.

Criminologists aren’t sure why fewer kids are getting in trouble. Some believe more kids are avoiding drug trafficking. Others think programs such as group homes, halfway houses and after-school tutoring closer to kids’ homes have reduced recidivism.

“No fancy stats suggest this is a cure-all, but what I think you do see is the accumulation of those small results of people doing this increasingly in cities and towns all across the country,” said Elliot Currie, a University of California-Irvine criminologist.

Those reforms have gained momentum as studies found teens sent to adult court often got in worse trouble after they were released and lawsuits emerged over poor conditions at state lockups. Many states have tweaked their juvenile polices so only the most serious offenders land in their systems.

“We’re locking up the right kids,” said Bart Lubow, program director for the Annie E. Casey Foundation, which helps fund such juvenile offender programs. “It’s about making smarter decisions.”

As a result, the number of juveniles in state institutions has dropped. According to the Justice Department, the number of juvenile offenders declined 26 percent between 2000 and 2008, from about 109,000 to 80,000.

All the empty beds offer states struggling with budget deficits a way to save money — downsize juvenile justice systems.