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 had operated for nearly 115 years. One in Texas will go quiet after getting its start as a World War II-era training base.

The closures have juvenile advocates cheering.

"I can tell you it's the best thing they can do," said Aaron Kupchik, a criminologist at the University of Delaware.

During the early 1990s, tough-on-crime legislators turned their attention to the juvenile system. Nearly every state lowered the minimum age for trying offenders as adults or expanded the list of crimes that could land young people in the adult system.

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

Criminologists aren't sure why fewer youths are getting into trouble. Some believe more are avoiding drug trafficking. Others believe programs such as group homes, halfway houses, and after-school tutoring closer to youths' 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 criminologist at the University of California-Irvine.

Those reforms have gained momentum as studies found that teens sent to adult court often got into worse trouble after they were released and lawsuits ensued over poor conditions at state lockups.

Many states have tweaked their juvenile policies so only the most serious offenders are incarcerated.

"We're locking up the right kids," said Bart Lubow, program director of the Annie E. Casey Foundation, which helps fund such juvenile offender programs.

As a result, the number of juveniles in state institutions has dropped. According to the Justice Department, the number of juvenile offenders fell 27 percent between 2000 and 2008, from 109,000 to 80,000.

In Pennsylvania, occupancy at state-run juvenile facilities is at 80 percent of capacity, down from 90 percent last year and 105 percent two years ago, according to the Department of Public Welfare.

In New Jersey, there has been a 38 percent reduction - from 1,078 to 664 - in the number of youths committed to juvenile facilities between 2000 and 2008. Though the Juvenile Justice Commission reduced its bed capacity by 7 percent over that period and has cut 4 percent more since, occupancy also has dropped, to 85 percent.

The empty beds offer states struggling with budgets a way to save money: Downsize juvenile justice systems.

For 2010-11, New Jersey's Juvenile Justice Commission has trimmed its budget by $10 million, or 8 percent, in part because of fewer intakes, a spokesman said.

In Wisconsin, state corrections officials are considering closing the Ethan Allen School, a former tuberculosis sanitarium near Wales, 25 miles west of Milwaukee. The school population has dropped from 460 in 1998 to 195 in May.

In Ohio, the system's residential youth population has fallen from 1,730 as of mid-2008 to 950 now. Its three closures over the last year should save about $40 million annually, according to juvenile corrections officials.

The number of youths in state residential custody in California peaked at 10,000 in 1996 but now is 1,500, state Department of Corrections and Rehabilitation spokesman Bill Sessa said.

The state has closed six institutions since 2003, most notably the Fred C. Nelles Youth Correctional Facility, which had operated just outside Los Angeles since 1890.

State officials keep the institution clean for film crews; the paranormal research television series The Othersiders investigated reports of sounds and voices there in an episode last year.

This article includes information from Inquirer staff.