McALLEN, Tex. — For thousands of undocumented immigrants in South Texas, the crowded bus station in downtown McAllen has become a new, impromptu Ellis Island. They line up daily, newly released from detention, having had no time even to put the laces back on their shoes. They hold government-issued bags with their few belongings close, and their children even closer.

July 18, 1:06 p.m. “I feel safer here than I did in Honduras.” Santiago Antonio Rodriguez Hernandez, with his 12-year-old son “We can work, we can go to school. We want to learn English.” Geronimo, 40, with his 17-year-old son “We walked over a mountain to cross the border.” Juana Susana Orozco Gomez, 21, with her 3-year-old daughter “It’s all for him. His life will be different. Very different. It’s good.” Mariben, 28, with his 1-year-old son “I feel safer here than I did in Honduras.” Santiago Antonio Rodriguez Hernandez, with his 12-year-old son “We walked over a mountain to cross the border.” Juana Susana Orozco Gomez, 21, with her 3-year-old daughter

Like Ellis Island, the bus station is a portal — an entry and exit point in the migrants’ monthslong journey to America’s Southwest border and beyond. Yet unlike that historic gateway on New York Harbor, all of the immigrants passing through the McAllen bus terminal — young or old, healthy or sick — have effectively been jailed by the authorities when they first arrived in the United States.

Today, most of the immigrants arriving at the border have fled their homes in Central America and traveled through Mexico. While some enter the United States in California or Arizona, a majority cross the Rio Grande in Texas, and then either turn themselves in or are caught by Border Patrol agents. They are detained in federal facilities in McAllen and other South Texas cities and then released.

Government-contracted buses drop many of them off at Central Station downtown. They stand in line outside, get their bus tickets inside and then walk to a nearby immigrant-services center run by Catholic Charities. They return later to board buses to cities across the country, where most will join relatives already living in the United States.

The national spotlight has been shining on the hundreds of migrant children who were separated from their relatives as part of the Trump administration’s zero-tolerance immigration policy. But thousands of other men, women and children continue to steadily and quietly arrive at America’s border.

They continue to come, regardless of politics or policies, or who occupies the White House. They do it, they say, because they want to escape violence, poverty or gangs in their native countries. Most these days are from Guatemala, Honduras and El Salvador, some of the most impoverished and chaotic places in the world.

“In our country, the state of the economy makes it very difficult to live,” said one 36-year-old mother of four, who traveled with her children from Olancho, Honduras, for 33 days and nearly 2,000 miles. “We’ve seen other cases of people finding success here, so we’re trying as well. This is the idea of immigration — come here and make a change for the better, right?”

TEXT “They’ve treated us well and they never separated us. I’m tired, but I’m O.K.” ARACELY QUINTEROS, 22, with her 2-year-old son “He’s excited to go to school. I’m excited to work. That’s what we want.” EUSEBIO, 48, with his 17-year-old son “I’m here to work. But it’s hard because I have two more kids in Honduras. This is for them.” JOSE, 41, with his 11-year-old son “I miss them,” he said of his kids. RAMIRO, 39 “They’ve treated us well and they never separated us. I’m tired, but I’m O.K.” ARACELY QUINTEROS, 22, with her 2-year-old son “He’s excited to go to school. I’m excited to work. That’s what we want.” EUSEBIO, 48, with his 17-year-old son “I’m here to work. But it’s hard because I have two more kids in Honduras. This is for them.” JOSE, 41, with his 11-year-old son “I miss them,” he said of his kids. RAMIRO, 39

One day last week, about 125 undocumented immigrants were released from detention and brought to the bus terminal. Four buses dropped them off in groups of roughly 30 from the late morning through the early afternoon. They stood behind a row of tattered traffic cones outside the Central Station’s side entrance.

Some gripped blue boxes that the authorities had handed them upon their release — inside were chargers for the GPS monitors they would now have to wear on their ankles. Some did not walk so much as shuffle, because their shoes were missing laces. While in detention, their shoelaces, considered potential weapons, were confiscated and then returned upon their release.

Most of the migrants had been held in custody only a few days, largely because they had no criminal history. The ankle monitors are intended to track their whereabouts and discourage them from escaping as their cases proceed through the immigration court system. Some have petitioned for asylum, fearing persecution in their native countries.

Rosa Marisol Vielman Marroquin, 31, stepped off the first bus from the detention center with her 11-year-old daughter at 10:50 a.m., the sleek black device on her right ankle locked above her unlaced hiking boots.

She and her daughter had left Petén, Guatemala, 15 days earlier. They were headed to New Jersey, to join her boyfriend there. “I left Guatemala because of the economic situation there, and for fear of the crime,” Ms. Vielman said. “I thought that the U.S. was a beautiful place.”

July 18, 1:42 p.m. “I want to work.” Mario, 31, with his

6-year-old son “In Nicaragua, the government made us fear for our lives.” Saida, 36, with her 10-year-old daughter “The journey to get here was difficult. We didn't want to do it. But we had to.” Nelson, 35, with his 5-year-old daughter “In Nicaragua, the government made us fear for our lives.” Saida, 36, with her 10-year-old daughter “The journey to get here was difficult. We didn't want to do it. But we had to.” Nelson, 35, with his 5-year-old daughter

Juana Susana Orozco Gomez, 21, stood outside the swinging glass doors of the bus terminal, holding her 3-year-old daughter in her arms. She spoke in a near-whisper as she described their journey from Guatemala, a trek that would be extraordinary were it not so common among those in the line. “We walked over a mountain to cross the border,” Ms. Orozco said.

She and the others assembled outside the bus station: alert, nervous, quiet or quietly talking. It was hard to imagine that some had risked their lives to stand there, paying thousands of dollars to the smugglers known as coyotes to guide them, or braving the journey on their own.

Hundreds of bodies have been found in recent years in the desolate South Texas brush north of the bus station — migrants like themselves whose journey had ended in dehydration, heat stroke or hypothermia.

Migrants walked from the bus station to a nearby immigrant-services center.

Migrants walk from the bus station to a nearby immigrant-services center.

On the fourth and last bus of the day was a 36-year-old woman and her 10-year-old daughter. They had left their native Nicaragua two months prior. “I thought something was going to happen to me on the journey here, but thank God, nothing did,” said the woman.

A few standing in line with her spoke of hunger, and of overcoming difficulties they declined to detail. Inside Central Station, his travel to New Jersey finally arranged after talking to the clerks behind the counters, one man who had left Honduras on the Fourth of July stared at the lobby floor, choking back tears when asked about the family he left behind. His 12-year-son stood silently next to him.

The man, Santiago Antonio Rodriguez Hernandez, couldn’t get the words out to explain his emotion. In his hands he clutched, as if they were precious, two items that had been given to him and other migrants on their way to the terminal. They were the first gifts they had received in America: red apples.

July 18, 11:30 a.m. “We left Guatemala to provide a better future for our kids.” Lesvia López, 33, with her children “After everything that’s happened and all that we’ve experienced — hunger, cold, sleeping here — I’m feeling happy.” Yerlin Yulisa Flores, 26, with her two children “We left Guatemala to provide a better future for our kids.” Lesvia López, 33, with her children “After everything that’s happened and all that we’ve experienced — hunger, cold, sleeping here — I’m feeling happy.” Yerlin Yulisa Flores, 26, with her two children

They arrived overdressed for Texas in July. Some wore sweatshirts or jackets, or had them draped over their arms or tied around their waists. Many had just been released from a place migrants have named La Hielera — The Cooler, or The Icebox.

That’s what they call the Border Patrol’s processing center on Ursula Avenue in McAllen, known for its frigid temperatures. Detainees keep warm with blankets that resemble giant sheets of aluminium foil.

Ms. Vielman, the woman from Petén, Guatemala, was detained there for five days with her 11-year-old daughter, Yerlin. She spoke of the cold, and of being in a separate holding area from her daughter — she could see Yerlin, but only from far away.

“We couldn’t talk to each other except for an hour each day,” Ms. Vielman said. “It was hard, but I told my daughter to be strong and to not cry, and that we were going to be O.K.”

As she spoke, volunteers hovered nearby. All of the immigrants released at the bus station are assisted by Catholic Charities of the Rio Grande Valley, which runs an immigrant respite center blocks away. Their volunteers help the migrants get their bus tickets and escort them to the respite center, where they can eat, rest, call relatives and put on new clothes, all without charge.

Without the assistance of Catholic Charities, and the ad-hoc, orderly system they established, the scene in the bus station would be confused and chaotic.

The roughly 125 migrants dropped off at the bus terminal that day were a typical number. Since 2014, the respite center has assisted nearly 100,000 migrants released at the downtown bus station.

Last week, the migrants spoke as much about the future as the past. They were headed across the country to new cities, and all had hearings and appointments scheduled with immigration officials in those cities. Their immigration status, at that moment, was uncertain. But they were eager for whatever was coming next.

“I want to work in Miami,” said Gerardo Mendoza, 27, from Honduras.

“I want to play soccer at school,” said Anthony, 16, from Guatemala.