Many of the arrests took place at immigrants’ homes, as teams of agents spread out in the early hours of the morning to catch people before they left for work, a common tactic designed to avoid a public scene. But agents also have been moving more aggressively, taking into custody people who arrived for routine check-ins, and even apprehending people arriving at courthouses on nonimmigration matters.
The rapid increase in arrests was primarily the result of one of Mr. Trump’s first significant immigration moves, rescinding rules laid down by former President Barack Obama that prioritized the arrest of the most serious criminals and largely left other undocumented immigrants alone. More than half of the increase in arrests were of immigrants who had committed no crime other than being in the country without permission.
Mr. Obama’s policy was rooted in both humanitarian and budgetary reasons, but to Mr. Trump and his supporters, and many ICE agents, it represented a failure to enforce the law and a de facto amnesty for millions of people in the United States illegally.
Supporters of Mr. Trump’s immigration policies welcomed the news. “I feel that’s one step in the right direction, I definitely feel that way,” said J. D. Ma, a lawyer in Clarksville, Md., who voted for Hillary Clinton but agreed with the president on immigration. “The reality is that if you don’t do that, that’s going to encourage wave after wave and disrupt the order of the society.”
At the same time, the wider net has frustrated some local law enforcement officials who have pointed to evidence that arrests, especially those at courthouses, were discouraging undocumented immigrants from reporting crimes. Since Mr. Trump was elected, reports by Latinos of sexual assaults and domestic violence have declined sharply.
“What it tells me is that the department is willing to put enforcement numbers ahead of any kind of strategy that would actually try to keep us all safer going forward,” said Omar Jadwat, the director of the Immigrants’ Rights Project at the American Civil Liberties Union.
Aware of the criticism, the federal authorities have frequently noted that a majority of those arrested — 75 percent in Mr. Trump’s first three months — were still people with criminal records.
Those swept up have committed a broad range of offenses. Guadalupe García de Rayos, a mother in Arizona, had used a false Social Security number to work at a water park. Juan Antonio Melchor Molina, a fugitive from Mexico, is wanted on a murder charge.
Although agents are no longer limited in whom they can pick up, Mr. Homan said that more than 2,700 of those arrested had been convicted of serious crimes like assault, rape or murder.
“If you look at the numbers, the men and women of ICE are still prioritizing these arrests in a way that makes sense,” he said.
Mr. Trump’s policies also appear to have slowed the flow of people crossing the southern border illegally, which has reached its lowest number in years, as migrants are choosing to seek refuge in other countries or endure poor conditions at home.
Unless they have already been ordered deported by a judge, immigrants who are arrested can plead their case in immigration courts, which have been snarled by a backlog that exceeds half a million cases. Over all, Mr. Homan said that deportations were down 12 percent from the previous year, partly because of a steep decline in illegal border crossings.
The increase in arrests under President Trump is less stark compared with 2011, when President Obama’s immigration agency apprehended 351,029 people, or about 29,000 a month. But arrests and deportations decreased in the years that followed as the Obama administration narrowed its focus to serious criminals.
Other aspects of Mr. Trump’s immigration agenda have not produced such quick results. His border wall has yet to be funded by Congress and his travel bans have been blocked by courts. Last month, a federal judge in San Francisco halted the Justice Department’s plans to financially punish so-called sanctuary cities that limit how much local police and jails may cooperate with ICE.
But at the current rate of arrests, ICE may surpass the highest annual numbers it reached under Mr. Obama in Mr. Trump’s very first year.
“That’s great news!” said Scott Hayes, a landscaper from Beverly, Mass. Mr. Hayes said he lost two more accounts this year because he was undercut on price, one of them, he believes, to illegal immigrants.
He said the changes under Mr. Trump were being felt in his area. Mr. Hayes said he was going out to mow a lawn last week and a friend from another landscaping company came running up to him. The friend said the owner of that company was furious with Mr. Trump.
“I said, over what?” Mr. Hayes said. “He said he can’t find any help! Trump is kicking them all out!”
Mr. Hayes added: “That’s why I was so passionate for Trump,” he said. “I wanted to expose these guys for who they are, if they are hiring illegal immigrants.”
An earlier version of this article referred imprecisely to one voter’s support for President Trump. J.D. Ma supports Mr. Trump’s policies on illegal immigration but voted for Hillary Clinton; he did not vote for Mr. Trump.