More than two-thirds of the cells at the Northern Virginia Juvenile Detention Center are empty on this gray, rainy morning in December, and not just because the 22 teenagers housed there are in classes or meetings in other parts of the facility.

For the past decade, the number of youths awaiting court dates or serving short sentences here has dropped by almost three-quarters — mirroring a nationwide decline in youth detention that experts attribute to falling crime rates and a turn toward alternative sentencing.

As a result, the three Northern Virginia communities — Arlington, Falls Church and Alexandria — that share the $5.8 million operating cost of the facility just south of Landmark Mall in Alexandria are wondering whether there is a better option.

The future of the detention center is a question that has divided advocates, employees and family members, who worry about jailing at-risk kids farther from home, or detaining teens in prisonlike conditions when they might be better served by alternative sentencing.

A cost-benefit study that is due in January will consider options including closing the detention center and sending juveniles instead to facilities in Fairfax or Prince William counties, changing how the facility operates or partnering with the juvenile detention center in Fairfax in an as-yet-undefined manner.

“This is a matter to be celebrated, that fewer youth are incarcerated,” Chris “Ike” Eichenlaub, vice president of the Moss Group, which was hired to conduct the study, said at a November community meeting. “It’s happening all over — Illinois, Nebraska, California and elsewhere.”

Although the United States still leads the industrialized world in youth incarceration and confinement rates, the numbers are rapidly falling. The Annie E. Casey Foundation’s Kids Count Data Center reports that about 107,500 were confined in 1999, compared with about 43,600 in 2017.

A report by the Justice Policy Institute, which advocates for reducing incarceration, says that rather than promoting public safety, the pretrial detention of youths accused of crimes may contribute to future offenses. Liz Ryan, chief executive of Youth First Initiative, an Arlington nonprofit group, said incarcerating young people as they await trial interrupts healthy psychological development, disproportionately affects youths of color, is unnecessary for public safety and doesn’t work as well as less costly community-based programs.

“Far fewer people need to be locked up to do the things detention is supposed to do for them — show up for court dates and protect themselves or others from harm,” said Carol Abrams of the Casey Foundation.

The foundation’s Juvenile Detention Alternatives Initative was inspired by a reform effort in Broward County, Fla., that reduced its detention population by 65 percent from 1987 to 1992. Authorities there cut the time it took to process cases, improved screening and promoted alternatives to locking up juveniles.

The shrinking of the jail population saved taxpayers more than $5 million, and did not raise crime rates, the Casey Foundation said.

Proponents of youth detention centers say there needs to be a place where young people accused or found guilty of misdemeanors as well as felonies can get help and learn discipline, such as following a regular schedule, abiding by rules and interacting respectfully with others.

In Seattle’s King County, however, officials are aiming to eliminate youth detention, focusing on prevention efforts and on addressing systemic bias that can lead to youths of color being locked up while their white counterparts are released. Other steps include diversion from incarceration through alternative sentencing, supporting families and improving coordination between government agencies that serve youths.

Derrick Wheeler-Smith, director of King County’s Zero Youth Detention program, said the county has reduced its use of juvenile detention to “one of the lowest per-capita rates in the nation.” But he said as numbers have declined, “racial disproportionality” among youths who are locked up has increased.

“Youth who are not white are seven times more likely to be in secure detention than white youth,” Wheeler-Smith said. “We’re working to combat this institutional racism.”

The youths placed in the Northern Virginia detention center by the juvenile and circuit courts in Arlington and Alexandria are judged to be at moderate or high risk of reoffending or to present a significant danger to themselves or others.

The average stay is three weeks. If youths are convicted and sentenced, they usually are sent to a longer-term facility in Chesterfield, Va., 110 miles away.

One parent, whose son has been incarcerated in the Alexandria center and other short-term locations for the past year as he awaits trial, said she has no issue with operation of the center, although she thinks it needs more services for teens struggling with mental illnesses.

“I think if they’re going to stay open, that would be fine,” said the mother, who spoke on the condition of anonymity to protect her son’s privacy. “If they move to another center, a lot of parents won’t be able to see their children as often because they don’t have vehicles.”

Johnitha R. McNair, executive director of the Alexandria center, said her staff works with parents who don’t have cars, even going so far as to pay for ride-sharing trips so they can visit when other options fail. McNair prefers to keep the facility open, arguing that the benefits outweigh the disadvantages.

“We try to be very treatment-focused,” McNair said while leading a tour of the low-rise structure this month. She pointed out the colorful murals that the youths painted on the previously beige hallways, and recent improvements in the outdoor space. “We do anger and behavioral management and teach life skills.”

Because of the plummeting population, an entire wing of the facility has been closed. The empty rooms, even in the parts of the facility that remain in operation, are stark: an elevated concrete sleeping platform that looks too high for small teens to ascend without a boost; a fluorescent light that can be turned down, but never off; and a stainless-steel sink-toilet combination that affords little privacy from staff members peering through the narrow window in the door.

But the rooms that are occupied explode with color — photos, art, letters, and blankets, pillows and chairs that the youths “earn” by following the rules. During the vast majority of the day, McNair said, the incarcerated youths spend their time in classes, one-on-one meetings with counselors or in the bright day rooms with others.

The center is not without controversy. It previously provided housing for immigrant youths under contracts with the federal Office of Refugee Resettlement and Immigration and Customs Enforcement, arrangements that brought millions in revenue. The center ended the contracts in the past two years, amid political pressure and community outcry.

Alexandria Mayor Justin Wilson (D) said new federal laws required more staff at the facility, to guard against sexual assaults. Given the low numbers of incarcerated youths both locally and regionally, he said, he wanted to examine the facility’s future.

“We have to be good stewards of the taxpayer dollar while trying to get the best outcome and environment for these kids,” Wilson said. “None of this effort is a statement on the quality of that facility.”

It’s unclear whether the three governments could close the center even if they conclude they want to do so. Patricia Hennig, one of two Alexandria appointees to the Juvenile Detention Commission of Northern Virginia, said the commission has owned the site since the 1950s, an assertion that the study is examining.

Hennig also argued that selling the property “won’t save any money,” because Arlington, Falls Church and Alexandria would have to pay per-diem costs to another detention center, as well as pay for transportation and time for sheriff’s deputies and probation officers.

The three governments also would have little say in how those centers are operated, Hennig said. At several public meetings, she called the study a “land grab” by Alexandria, a charge that Wilson flatly denies.

Wilson said he has not made up his mind about what he would favor for the center.

After the local governments receive the study, he said, there will probably be community hearings and a joint meeting of the officials involved. There is no deadline for action.