The Homestead shelter has been the subject of close scrutiny in recent days, as overcrowding at migrant facilities along the border has led to growing concerns about the handling of migrant children not just at the border, but across the country. For several days, the Trump administration has been under attack for filthy housing conditions observers saw at a border station near Clint, Tex.

On Wednesday, ahead of the opening presidential debate, a parade of Democratic presidential contenders streamed out to the Homestead facility to criticize the conditions under which migrant children are being held at facilities along the border.

“What is happening at Homestead to children — what is happening as the direct result of activities of the United States government — is wrong,” said Senator Elizabeth Warren of Massachusetts, who led the pack. “It is a stain on our country, and we must speak out.” Following Ms. Warren later in the day were Senator Amy Klobuchar of Minnesota and Jane Sanders, the wife of Senator Bernie Sanders of Vermont.

Children living at Homestead have complained that it is extremely crowded and noisy, and that they enjoy no privacy, according to reports filed with a federal court. They report feeling increasingly despondent because they have no idea when they will be released, lawyers said. Rules prohibit them from listening to music or writing in a journal. Some reported having suicidal thoughts.

Amy Cohen, a psychiatrist who has visited the facility, said the noise level was extremely high, especially in a tent with no soundproofing where “children are crammed” and teachers must use microphones to be heard above the noise.