TIJUANA, Mexico—On the U.S. side of the border, an immigration officer unlocked a padlock on a metal door. On the other side, a Mexican officer unlocked another padlock. With that bit of antiquated protocol, the metal door opened, and Antonio Gomez stepped back into the country he'd fled as a boy.

View Images A man rests on a bench inside Casa del Migrante, a shelter run by Catholic priests that frequently houses Mexicans who have been deported from the United States.

It was the first time Gomez had been in Mexico in 34 years.

"I feel dizzy," he said later, sitting on a bench at Casa del Migrante, a shelter run by Roman Catholic priests atop one of Tijuana's many hills. "I can't believe this has happened to me."

Gomez had crossed the border illegally alone in 1980, at age nine. He slept under a freeway overpass when he was 12. Over the next few decades, he struggled. But by 43 he was a husband, father, and co-owner of a small construction company.

One Saturday night last year an agent from U.S. Immigration and Customs Enforcement came to the apartment in Ontario, California, where Gomez and his family were watching TV. The agent was looking for another man. He took Gomez instead.

A year later, after several court hearings, U.S. immigration officers loaded Gomez, and 20 other deportees, into white Ford vans and drove them to the border.

Gomez, a thin, polite man with glasses and a mustache, spent his first night in Tijuana with a hundred other recent deportees in Casa del Migrante. "I don't know what pesos are," he said. "I feel like I'm in a dream, in another world."

It's a world in which tens of thousands of traumatized deportees like Antonio Gomez have been dropped in Tijuana and have stayed.

In the last five years, the United States has deported record numbers of immigrants, including roughly 250,000 to 300,000 each year to Mexico. Mexico has 15 repatriation points, but one-third of all deportees are usually sent to Baja California, and half come through Tijuana—from 100 to 300 every day, officials here say.

View Images EMILY M. ENG, KELSEY NOWAKOWSKI, NG STAFF. SOURCES: U.S. Department of Homeland Security; Mexican National Institute of Migration

On Thursday, President Barack Obama announced a reprieve for more than 4 million immigrants in the United States illegally, primarily parents of children who are citizens or legal residents. The step, which the president said he took because Congress has failed to act, will slow deportations to Mexico. But it comes too late for Gomez and others already in Tijuana.

For years, Tijuana thrived on the energy and optimism of Mexico's poor, who passed through on their way to a better life in the United States. They "had the American dream in their heads, with optimism and the desire to work. They were going to pick money off the street," said Gilberto Martinez, administrator of Casa del Migrante.

But in recent years, many of these people, like Gomez, have been sent back, "sad, exhausted, beaten, as if they're coming from a funeral," Martinez said.

They stream through rooms of gleaming tile and fluorescent light, where Mexican government workers offer them medical checkups, food, health insurance, and a phone call or a charge for their cell phones. After that, they are largely on their own.

"Think of them as falling from a building," said Rodulfo Figueroa, director of the Tijuana reception center. "We try to prevent them from hitting the ground at 30 miles an hour."

Some return to their hometowns using the free plane and bus tickets the Mexican government provides. But about one-third stay, officials say. No Mexican border city has absorbed more deportees than Tijuana.

View Images Men come and go from their rooms in the atrium of Casa del Migrante. The shelter was started in 1987 to house migrant workers on their way to or from the United States.

Returned to a Country They Hardly Know

These men—90 percent of the deportees are men—live in a kind of limbo. Most have been in America so long that they have lost ties to Mexico. They remain in Tijuana to be close to their families in the United States, to try to cross again, or because they no longer know anyone in their Mexican hometowns. Many have no papers to show they belong in Mexico and so finding work is close to impossible.

Their families in the United States often send money at first. But typically that stops, leaving a deportee to fend for himself.

View Images MAGGIE SMITH, NG STAFF. SOURCE: U.S. DEPARTMENT OF HOMELAND SECURITY

They are everywhere in this city of more than 1.3 million—lone men in jeans and ball caps, carrying small backpacks. They are unwashed and deeply tanned; many spend all day in the sun cleaning windshields at stoplights or selling fruit.

Outside the Padre Chava breakfast hall, a soup kitchen in downtown Tijuana run by a Catholic order of priests, hundreds of men form queues every morning that conjure up Depression-era breadlines. Once inside, they wash their hands and dry them with paper towels handed out by the staff. They stand beside tables to be blessed, then they're eating—quickly, as volunteers hover, waiting to prepare the tables for six more.

"I wasted a lot of opportunities in the United States," said Marco Luna, who said he was in a South Los Angeles gang and used drugs. "But I sure wish Obama would give me another one." Luna, 32, was deported this summer. He now washes windshields for tips and eats at Padre Chava.

Staff at the breakfast hall estimate that the roughly 1,200 homeless deportees they serve every morning are a small fraction of the number in the city.

"The great majority is here because they began to feel great confidence living in the U.S.," said Margarita Andonaegui, co-founder of the breakfast hall.

View Images Hundreds of men, many deported from the United States, line up outside Padre Chava breakfast hall. They eat quickly so the tables can be reset for the next diners.

The Ripples of the U.S. Crackdown

That attitude grew largely from the schizophrenic U.S. approach to immigration enforcement over the last three decades.

In 1986, Congress passed the Immigration Reform and Control Act, which made hiring an undocumented immigrant a crime. But American business owners and homeowners who employed them were mostly given a pass. In Mexico, anyone who could make it past the border was widely believed to have an excellent chance of finding work and setting up a life in America.

Two decades later, the number of immigrants in the United States illegally was estimated at close to 12 million; more than half were from Mexico. They worked, married, and had children. Some bought houses or, like Gomez, opened businesses. They made lives of relative stability without documents.

For years, the reigning ethos was "your work gets you through the world," said Jose Luis Garcia, 33, who was born in the Mexican state of Guerrero but lived half his life in San Clemente, California, as a construction worker before being deported last spring.

Then all that changed.

View Images After washing and drying their hands, men wait patiently and quietly in a fast-moving line at Padre Chava, a soup kitchen run by an order of Catholic priests.

View Images Volunteers at Padre Chava serve a simple but hearty meal: beans, rice, tortillas, coffee, and atole—a drink made from water, cornmeal, cinnamon, and brown sugar.

President George W. Bush, thwarted by his own Republican Party in his bid to revamp immigration laws, instead stepped up deportations to show his commitment to enforcement. Under Obama, deportations have increased.

The Obama administration has insisted that most people it has deported had criminal records. But two-thirds have committed only minor infractions or, like Gomez, no crime other than being in the country illegally, according to figures that U.S. Immigration and Customs Enforcement provided to The New York Times this year.

All this has come down like a hammer on Tijuana. Its government—underfunded, like all Mexican city halls—struggles to absorb the sudden surge of homeless deportees.

Merchants here believe that nothing has been done about increases in petty crime and vagrancy and are unsettled by the desperate deportees wandering their city.

"I come to my shop in the morning, and they've defecated in front of it," said one merchant, whose curio store is near the Padre Chava breakfast hall and did not want to be identified for fear of retribution. "I know they're suffering, but this is too much."

Many hundreds of deported southern California gang members have congregated in Tijuana, their ominous tattoos announcing their affiliations. Police believe that some have joined drug cartels as gunmen. Deported along with Gomez were at least three men with prominent L.A. gang tattoos.

"The U.S. government is saying, 'You deal with them. They're not mine,' " said Karim Chalita, the city's representative for Tijuana's downtown district. "I wish we could absorb the people who are coming. But the municipal government can barely deal with the issues that face it day to day."

View Images Apprentice barbers, who are earning work credits to help them find jobs in professional salons, provide free haircuts at Padre Chava.

'They Arrive Almost Naked'

Perhaps the most draining effect on Tijuana comes from the arrival of thousands of broken men who cannot legally work because they are undocumented in the country of their birth.

Hoping to rectify that, the city plans to open offices where deportees born in several Mexican states will be able to get their birth certificates—the first step toward assembling the documents needed to find a job in Mexico. And the country's electoral agency plans to step up efforts to get them voter registration cards, a form of identification commonly used in Mexico.

"We're all used to carrying around American Express cards and all the rest," said Carlos Mora, president of the state Migrant Assistance Council. "But they arrive almost naked, without anything. When you have a new identity, you have a new person."

View Images About two dozen men from Casa del Migrante attend Mass. During the week, they had practiced singing hymns with a small group of church musicians from Mexico City.

Immigrants in the United States illegally have shown remarkable ability to adapt to life in the shadows, but always with the promise of better days ahead. Tijuana's deportees strain to show that same resiliency, knowing their wages—considered a measure of their value as men—will never be close to what they once earned. Tijuana is believed to have Mexico's highest working-class wages, but they are one-tenth those in the United States.

Many who are marooned in Tijuana didn't invest much in their own skills in the United States, eschewing school in the belief that a construction job was enough to do well. Many speak English, but not fluently, even after years in the United States. In Mexico, meanwhile, they've found construction work to be among the most competitive, poorly paid work.

Moises Vazquez, 36, who grew up in Pasadena, California, was deported while facing drug and domestic violence charges this year. He now works as a security guard in Tijuana for 12 hours a day, seven days a week. As a night-shift supervisor, he is paid the equivalent of $1.50 an hour. As a construction worker in California, Vazquez could earn more than $15 an hour.

"I haven't put my mind in TJ," said Vazquez, using a nickname for Tijuana. "For me, I'm American. I was born in Mexico, but I was raised over there. I'm never going to adjust to this. I'm going back; with God's help, I'm going back." Vazquez left behind a wife and two kids in Pasadena.

View Images A homeless man heads to the Tijuana River after crossing Via Internacional, which runs along the U.S. border. Downtown Tijuana looms in the background.

A Daily Search for Food

The depth of the depression that crushes many deportees, and its effect on Tijuana, is best embodied by El Bordo—the paved section of the Tijuana River that runs north through downtown and into San Diego and the Pacific Ocean.

Years ago, the city's poorest arrivals from Mexico's deep south colonized the riverbed, forming a shantytown known as Cartolandia (Cardboardland). In the 1970s, Mexico's government, ashamed of the open sore displayed to foreign tourists, tore down Cartolandia.

Today, though, the riverbed is again a home, this time to hundreds of people who sleep by the channel of effluent. Many Bordo denizens are locals, but a good number are deportees. For some, the trauma of a life upended has led them to wither away into the riverbed's drug-hazed life. Others, without Mexican documents or work, can find no other place to sleep.

Garcia, the construction worker from San Clemente, has called El Bordo home for many of the nights since he was deported last spring, after he was arrested for drunken driving. He hasn't seen his fourth child, who was born four months after he was deported. Garcia knows no one in his hometown of Iguala, Guerrero, which he left as a teen. He's stayed in Tijuana to remain close to family in the United States.

View Images Many of the men deported from the United States lack the documents needed to prove they are Mexican, making it almost impossible for them to find work. Some sell fruit on the streets; others wash car windows for tips at intersections.

Every day in Tijuana is a search for food, and hopefully shelter too. But when that doesn't happen, Garcia returns to El Bordo. Standing beneath a massive bridge support, he said, "There are about 60 or 70 of us who sleep under this."

Garcia nods toward an encampment of plastic tarps and plywood shacks about 200 yards (182 meters) away. "The other communities up there are made up mostly of people who are doing other things that it's best not to talk about for our own protection," he said.

As he spoke, a man urinated behind him. Another washed clothes in the stinking water. Others lay on ratty sleeping bags and blankets. Several begged for pesos from pedestrians on the bridge.

A bread distributor occasionally stops by to donate to the migrants. "Sometimes others will pass by with donations for us," Garcia said. "Otherwise we have to go looking for our daily bread."

For Antonio Gomez, the first few days back in Mexico were painful. He bought a cell phone in Mexico and found a church to attend. He called home. His brother-in-law had moved in to help support his family. His children cried for him to come back.

The enormity of his sudden change of life became clear to him as he crossed an overpass and stopped to watch the traffic below.

"I don't know nothing about this country," he said.

View Images A man deported from Los Angeles County leans on makeshift bedding in an area of the Tijuana River known as El Bordo. He and about 15 other deportees watch each other's backs and belongings. Beyond the bridge, the riverbed is occupied by drug addicts.