For several nights last week, New York City’s migrant crisis seemed to have passed a breaking point: As many as 300 newly arrived migrants were left to sleep on the sidewalk outside the main processing center in Midtown Manhattan.

Mayor Eric Adams said the city had simply run out of room in its sprawling, ever-growing network of emergency shelters, after receiving nearly 100,000 immigrants since last year. Images of men crammed behind metal barricades in a line that wound around a Manhattan block drew comparisons to migrant surges that have overwhelmed the streets of European countries and chaotic tent cities on the West Coast.

But by the end of the week, the overnight line had disappeared.

So where has the city been putting everyone? That remains a bit of a mystery.

It is not as if migrants have stopped coming. On Wednesday, the city said that 2,900 more had arrived in the past week — up from 2,300 the week before.

Part of the answer can be found at a large church in Long Island City, Queens, the Evangel Christian Center, which the city said accepted nearly 200 people last week who had been in the line outside the Roosevelt Hotel, which has become the main intake center for migrants. Several migrants from the West African nation of Mauritania said Wednesday that they had been moved there from their sidewalk sleeping spots.

Mohammed Yerim, a Mauritanian in his mid-20s, said he came directly to the church, bypassing the line outside the hotel, after arriving from Florida.

“I came here because I have a church address” that someone had given him, he said, adding that the accommodations, including halal food and showers, were “very good.”

The city declined to release a breakdown on where it is housing the most recent arrivals or the 50,000 migrants it is currently sheltering, but offered some piecemeal information accounting for several hundred new placements.

Two emergency lodgings in recreation centers in Brooklyn in McCarren Park and Sunset Park that opened over the weekend are housing about 80 people each. The city found hotels upstate to take about 75 people over the last week, officials said, and is expanding the capacity of a humanitarian relief center in Clinton Hill, Brooklyn. A small number of migrants leave the shelter system each week after finding homes elsewhere.

Power Malu, who runs the volunteer migrant-aid group Artists Athletes Activists, said that dozens of families who came in on buses from Texas on Wednesday were sent to the 250-room Redbury Hotel in Manhattan, where a city migrant shelter has just come online.

Some private aid groups and advocates for migrants have expressed skepticism that the city ever really ran out of room to begin with. They suggested that the line of sleepers outside the Roosevelt represented not a system that had temporarily broken down and been patched back together, but a gambit by the city to amplify its pleas for more outside help.

Last week, a lawyer for the Legal Aid Society said the city “could shelter everyone who is on that sidewalk if that is what they wanted to do.” Mr. Malu and other advocates said the city was also making people sleep outdoors to discourage migrants from coming.

“The greater he makes the crisis seem,” the more leverage the mayor has to get money from the federal and state governments, Ilze Thielmann of the volunteer group Team TLC NYC said on Wednesday.

Kayla Mamelak, a spokeswoman for Mr. Adams, bristled at the advocates’ suggestion that the Roosevelt line was any sort of ploy.

“Their implication is that it is some kind of political stunt,” she said on Wednesday. “That’s insulting. It is not. This is a very real situation.”

Last Wednesday, the Legal Aid Society sent a letter to the judge hearing the city’s request to be relieved of its unique court-mandated obligation to provide a bed for every homeless person who requests it. The letter stated that the city was violating the right-to-shelter rule and requested an emergency hearing. The judge, Erika Edwards of State Supreme Court in Manhattan, granted the hearing, and by the next morning, the line was gone.

After the hearing, Justice Edwards ordered the city to file a proposal by Aug. 9 “identifying the resources and facilities owned, operated and/or controlled by the state” that it needed in order to continue sheltering all comers. The mayor welcomed the judicial attention to the matter, saying in a statement that “unless the state and federal governments fulfill their obligations to join us and do more in supporting asylum seekers, scenes like the one that broke our hearts outside the Roosevelt may sadly become more common.”

Mr. Malu said that the city was needlessly making it harder for migrants to find shelter. He said that last week, nonmigrants who went to the city’s main intake center for homeless single men on East 30th Street were sent to Department of Homeless Services shelters, while migrants who went to the same office were sent to the line outside the Roosevelt.

“It’s not that the city is out of space; it’s that they’re doing segregation,” he said.

Ms. Mamelak said she was not aware of such a practice at East 30th Street.

Meanwhile, the city continues its scramble to find places to put people — a task that Mr. Adams said on Wednesday was on track to cost $12 billion over three years.

In coming weeks, it plans to open a tent complex in the parking lot of a state psychiatric hospital in Queens and, bringing some of its earliest efforts full circle, a tented dormitory for 2,000 people on Randall’s Island off Manhattan, where it had opened and then closed a similar facility last fall.

Adama Bah, a community organizer who has been meeting buses of migrants at the Port Authority bus terminal for over a year, said that on any given night, there are hundreds of migrants sleeping in houses of worship (which receive $65 per night per person from the city) and in the homes of New Yorkers.

“We have people sleeping in basements, we have friends that are opening their doors, we have migrants sleeping in parks, we have migrants literally sleeping anyplace they could feel safe,” Ms. Bah said.

On the Lower East Side of Manhattan, a resident of a city public-housing complex, Camille Napoleon, has hosted as many 12 migrants at a time in her two-bedroom apartment, on couches and cots and — in the case of one man from Colombia who had slept on a floor his whole life — on a rug on the floor.

“My living room has been their room,” said Ms. Napoleon, 51.

On Wednesday night, Wilfran Moreno, 32, who left his wife and two children in Venezuela earlier this year and arrived at Ms. Napoleon’s apartment on Monday, was sitting on a sofa, watching TV and playing with her dog, who came from another migrant family and now lives at Ms. Napoleon’s home. He said he was looking for work as a mechanic or truck driver and was “speechless” with gratitude at having a place to stay.

“It’s like home, like being back in my home,” he said.