Underneath the borough lives a shadow city of illegal apartments, shielded from the light.

Owners of one- and two-family homes have carved up their basements into makeshift dorms, illicitly constructed with narrow hallways, windowless bedrooms, shaky walls and electrical wiring strung together like knotted shoelaces. There is no accurate count of how many exist, but estimates are in the tens of thousands.

An open secret, the basements are a haven for thousands of people who work in restaurant kitchens, on delivery bikes, in small factories or on construction sites.

They live in tiny rooms alone, or share tight spaces with strangers, or even sleep in shifts.

The small, dark room where Amado stays costs $650 a month. His share is $325. His roommate is undocumented, and so is his roommate’s brother, who earlier this year frequently stayed over and shared a twin bed. The brothers slept head-to-toe, back-to-back, while Amado lay on his twin bed, quietly reading the Old Testament.

In his corner of the room, the glow of a small television set played the news and telenovelas, offering some brightness.

He squinted, even in glasses.

Queens is the city’s most diverse borough, with 800 languages spoken among its residents. Vendors work long into the night because people are always on their way to or from work.

All over, “FOR RENT” signs dot windows in homes and cover electrical poles. There is no explanation of the rules, and no warning of danger. The basement apartments differ considerably in size, quality and legality.

The threat of raids by immigration authorities had residents on edge during the summer. But immigrants said they still feel a great deal of protection in Queens, where there is more access to free legal help to assist them with their cases.

They can also find housing that is less expensive than in other places, even if it does not meet city building standards. Eight areas in Queens are consistently among the top 10 places in the city with the most complaints for illegal home conversions.

City law says a basement’s ceilings must be at least 7 feet 6 inches high. Living spaces must have a window. The city must approve apartments with a certificate of occupancy before they can be rented.

Such rules make practically all of the basement housing stock in Queens illegal, including Amado’s home. The ceilings where he lives are just under seven feet high and the space has no visible smoke detectors. More than half of the apartment sits underground, which technically makes the home a cellar. In New York, all cellars are illegal dwellings.

Amado’s room shares a window with the room next to his. He cannot use it as an exit in case of an emergency. It is too small. And if he opens or closes the window, it affects the other room, like a window that sits between two rows on an airplane.

But the basement apartment was eventually filled again. Amado moved in a few years ago after spotting a sign in a window. Most of the time he and his roommates stay quiet. The only visible sign of life is the light coming through the slots under the men’s closed bedroom doors.

At the entrance of the home of Sosimo and Dalilia, there is a tangle of wires, like a messy plate of spaghetti that stuck after being thrown on the wall.

The married couple work in dry cleaning and live with two other men in a wood-paneled basement deep underground.

They moved there when their daughter, Jessica, now 27, went to college so they could help with tuition. They had previously paid $1,600 a month for an apartment. They now pay $500 a month for their room.

The narrow kitchen is taken up by a stove attached to a propane tank that was designed for outdoor cooking. But they cannot use the setup in the summer because it heats up the apartment to uncomfortable temperatures.

In a common room, Sosimo records his amateur radio show that draws listeners from New York, Los Angeles and his native San Andrés Solaga in Oaxaca, Mexico. Sosimo took up radio hosting about two years ago.

Some residents have been able to find basements that are structurally sound, including Itamar Bispo, a 76-year-old guitarist, who lives in an apartment that has windows in every room and two easy exits.

But he must walk through the landlord’s office to get to his apartment, which is labeled “OFFICE” on the door.

His bathroom is outside his apartment in the real office, and he has no stove. His refrigerator sits next to a chest of drawers.

In a corner of the room that serves as both the kitchen and living room, he makes music, setting up his microphone and singing tunes. “You only need one song,” he says, still hoping to make the hit record that eluded him in his youth.

For now, his retirement benefits and an occasional recording gig are just enough to afford the $850-a-month apartment.

There are exceptions to the darkness and loneliness that can come with living underground. Oksoon Son, 65, moved about two years ago into the basement of the house her daughter and son-in-law rent, wanting to help raise her grandchildren.

Ms. Son, a retired nail technician, first arrived in Queens from South Korea in 1980. After living in a homeless shelter, Ms. Son raised her daughter and son in Queensbridge public housing.

“I like this place,” she said in Korean one afternoon as light from the windows filled it up. “The sun.”

That’s what Amado wants. A little sun, which he gets briefly when he walks to work, six days a week, at the restaurant where he’s worked for 11 years.

Amado, who is in his 50s, has lived in the United States for nearly 29 years, coming by way of a smuggler through California, on a bus, first to Brooklyn with a brother, then to Queens. He is now in the country legally and able to travel back and forth to Mexico.

“I was the first one in the family that arrived here,” he said in Spanish. “It was very difficult for me to be in this city. I was very afraid of, like, the escalators.” Amado laughed at himself.

He doesn’t have much of a social life in New York. On Wednesdays, he heads to Make the Road New York, a nonprofit organization that operates out of a storefront on Roosevelt Avenue. He owes them, he says, for legal assistance they provided two years ago when he had problems with his green card. He shows up to nearly every protest to lend his body and voice to whatever cause.

Otherwise he’s in his basement, where the glow from his phone, his lifeline to his family in Mexico, provides a little extra light.

A wall in Amado’s room reflects the sacrifice he’s made: Receipts tacked to the wall show bank deposits and money orders sent back to his wife in Coatzingo, Mexico.

Amado longs for Coatzingo, the village where he’s from, and where his family lives. He’s able to make the trip there only twice a year.

Life is different there. In Coatzingo, Amado switches his baseball cap for a cowboy hat, and an entirely different man emerges.

He is a well-regarded man in his village, a man with a wife, two stepdaughters, an extended family, friends. Some might even call him rich. He has a piece of land to call his own.

He basks in the sun. He swims in a cool, natural pool. He tends to the family cornfields and a few lime trees.

He caresses his wife, Justina, able to touch her and not just hear her voice in the dark in the basement.

He runs errands, he pays bills, takes care of his family, mundane tasks that bring him pride.

With the money he saves living frugally in the basement in New York, he is patron to both his family and the town, doling out his earnings to pay for small luxuries, like a large flat-screen television.

This is why he’s in New York. If Amado had stayed in Coatzingo, he most likely would not have a job that could support his family. The crops of the family farm bear fruit but earn little money.

He plans to stay in New York for at least another five years, when he thinks he will have saved enough money to live a secure life in Mexico and can give his daughters the option of living in the United States to pursue whatever dreams they might have.