It was 4 a.m., time for Latoya Iheanacho to gear up to take her children to school.

On many mornings last year, that was her routine as she bounced between homeless shelters in the Bronx and Queens with her son and two daughters. The trek to their New York City public school, by bus and two trains, sometimes took two hours. Ms. Iheanacho left her job in mental health care so that she could accompany them.

They often returned after dusk to mice-infested rooms. One of her girls entered puberty early, which doctors suggested could be a symptom of family stress. All of the children were falling behind in their classes.

“They didn’t even have energy to do homework,” Ms. Iheanacho said. “They were tired and hungry.”

“It was just constantly survival mode,” she added.

Their story illustrates how America’s affordable housing crisis has contributed to its worsening education crisis. The Iheanacho children were among the more than 1.3 million students in the United States identified as homeless, according to the most recent data, a figure that is widely considered to be a significant undercount.

Some go to bed in shelters or in cramped, overcrowded apartments. Others sleep in hotels, cars and other spots that are the last resort for people who are transient. They are all considered homeless under federal education law.

Their population has soared during the past decade, underscoring the urgent need to build housing. In Los Angeles, the growing number of children who lack adequate housing is fueling a surge in chronic absenteeism. In Syracuse, N.Y., skyrocketing rents have left record numbers of children without a home.

The consequences can be grave: Two homeless children in Detroit died this year from carbon monoxide poisoning while sleeping in a family van parked in a garage.

Children from families without stable housing face dismal educational outcomes and can fall into a brutal cycle. They are far more likely to drop out of school than their classmates — and failing to graduate is the single greatest risk factor for future homelessness.

Nowhere are these challenges more striking than in New York City, where the housing crunch is the worst it has been in more than five decades.

More than 140,000 children — over 15 percent of students — lack permanent housing. The city’s population of homeless students is larger than the entire enrollment of the Dallas public school system.

And as the Trump administration sunders the nation’s social safety net, some experts worry that still more children could be left without a permanent place to call home in the coming years.

New York’s mayoral race has been dominated by debate about the effects of the housing crisis on parents, single renters and average earners. But the youngest — and most vulnerable — victims of housing insecurity have received far less attention.

Mayor Eric Adams, who took office in 2022, has directed more funding to schools that serve homeless students and hired new staff members in shelters. The mayor has dropped his long-shot re-election campaign, and the growing number of homeless children in the nation’s largest school system is poised to emerge as a pressing problem for the city’s next leader.

Dave Giffen, the executive director of the Coalition for the Homeless, an advocacy group, said the increase in homeless students “is so profoundly obscene that I don’t know how the No. 1 priority of any administration isn’t ensuring that everyone in the city has a place to live.”

New York City has one of the highest rates of student homelessness among large U.S. school districts. Roughly 7 percent of Chicago’s schoolchildren and about 2 percent of Miami’s public school students were identified as homeless in recent years. (New York is difficult to compare with other cities partly because it is unique in its longstanding legal agreement to provide shelter to anyone who asks for it.)

The scale of the problem today is without precedent.

In 2018, roughly 130 schools in New York had at least one in four students who was homeless. Within five years, that figure had grown to nearly 330.

“Nobody is looking comprehensively at the needs of homeless students,” said Christine C. Quinn, a former City Council speaker and the chief executive of Win, the city’s largest operator of shelters for families with children.

“We have not made them a priority,” Ms. Quinn said. “The next administration has the ability to turn the page.”

School can be the greatest source of stability in a child’s life. But families engulfed by the disruption that accompanies homelessness can feel compelled to transfer in the middle of the academic year.

There are few spots available in shelters, so families frequently wind up far away from the schools their children attend: More than 40 percent are initially placed in a shelter in a different borough. That figure has remained stubbornly high across mayoral administrations, and experts point to it as an example of how the city fails to set up many homeless children for success.

Ms. Iheanacho, whose family recently secured a two-bedroom apartment in Queens through the city’s housing lottery, said she felt pressured at times to transfer her children, who are now 5, 11 and 13, to a closer school. But homeless students have a federal right to remain in the school they had been attending, and she feared that they would lose their community and feel lost in their classes if they left.

Every time homeless students move schools midyear, research shows, they can be set back by up to six months academically.

“They lose time, they can fall behind, and they can disengage,” said Barbara Duffield, the executive director of SchoolHouse Connection, a national nonprofit organization that focuses on homelessness and education.

Ms. Duffield said that while many cities focus on homeless single adults, “the next generation of homeless adults is literally being created if we don’t center schools in the conversation.”

In New York, education has not been a prominent theme in the mayor’s race. Former Gov. Andrew M. Cuomo, who is running as an independent, has said he wants to convert more schools that are serving homeless students into so-called community schools, which offer services such as dental care and adult education courses and can lead to better outcomes for children.

Zohran Mamdani, the Democratic nominee and front-runner, has frequently pledged to expand a pilot program in the Bronx — where more than one in four children in some neighborhoods are homeless — that connects families in shelters with city employees for regular check-ins to help them solve problems that can hurt students’ performance.

Still, Jennifer Pringle, a project director at the nonprofit group Advocates for Children who works with families in temporary housing, said that the next mayor would need to look beyond the Education Department to ensure success for homeless children.

“Schools can try as hard as they can,” Ms. Pringle said. But without more support from other agencies, “it’s just not going to move the needle.”

In a city defined by extreme wealth, some obstacles — like needing to buy an alarm clock to wake up on time, or finding a quiet space to complete homework — might be minor hiccups to more well-off families but can cause chaos for homeless children.

It is apparent in report cards: Roughly half of all homeless students are absent for at least 10 percent of the school year; many miss even more class time. Among children living in shelters, about 75 percent lacked proficiency in reading in 2023, according to the most recent public data, and more than a third did not graduate on time.

In interviews, experts pointed out that simple changes could significantly help these students.

The city’s schools chancellor has top deputies whose purview centers on other groups of disadvantaged children, such as those with disabilities. But no high-level official focuses solely on homeless students.

Preschool programs can be especially helpful for children from low-income families. But outreach efforts to families living in shelters have declined, and the enrollment of homeless students in prekindergarten has dropped since before the pandemic.

And for years, New York has struggled to improve a yellow bus system that City Council members called a nightmare at a recent rally. When Ms. Iheanacho’s children took the yellow bus, they could arrive hours late to school. She was warned that their attendance issues could prompt scrutiny from child welfare investigators.

Since moving into an apartment, Ms. Iheanacho said, her children have seemed less anxious about their future. But she remains worried that any unexpected problem — the loss of her job or trouble renewing her lease — could send their family back into a shelter.

“It’s scary that we could be facing this again in two or three years,” she said.