Even though hundreds of children separated from their families after crossing the border have been released under court order, the overall number of detained migrant children has exploded to the highest ever recorded — a significant counternarrative to the Trump administration’s efforts to reduce the number of undocumented families coming to the United States.
Population levels at federally contracted shelters for migrant children have quietly shot up more than fivefold since last summer, according to data obtained by The New York Times, reaching a total of 12,800 this month. There were 2,400 such children in custody in May 2017.
The huge increases, which have placed the federal shelter system near capacity, are due not to an influx of children entering the country, but a reduction in the number being released to live with families and other sponsors, the data collected by the Department of Health and Human Services suggests. Some of those who work in the migrant shelter network say the bottleneck is straining both the children and the system that cares for them.
Most of the children crossed the border alone, without their parents. Many are teenagers from Central America, and they are housed in a system of more than 100 shelters across the United States, with the highest concentration near the southwest border.
Stories of such behavior have emerged through reporting in recent months as the shelter system has faced intense criticism by members of Congress and the public.
“Being in congregate care for an extended period of time is not a good thing. It increases the likelihood of things going wrong,” Mr. Greenberg said.
The administration funneled children who were separated from their parents into the shelter system this summer under the earlier policy, without any apparent collaboration with the officials who oversee the shelter program.
The separated children injected a new degree of chaos into the facilities, according to several shelter operators, who spoke anonymously because they are barred by the government from speaking to the news media. The children were younger and more traumatized than those the shelters were used to dealing with, and they arrived without a plan for when they could be released or to whom.
But the system had already been overwhelmed for months, operators said, as children continued to flow in while fewer were being discharged.
The shelter system has overflowed before. In 2014, when unaccompanied children flooded across the border in unprecedented numbers, a lack of shelter space led to a backup of children at the border in what authorities referred to at the time as a humanitarian crisis.
Since then, new facilities have been constructed or arranged by contract — and they are now nearing capacity.
A version of this article appears in print on , on Page A18 of the New York edition with the headline: Shelters Near Capacity As More Youth Migrants Are Detained Than Ever