Apps and ankle monitors that track asylum seekers in real time wherever they go. Databases packed with personal information like fingerprints and faces. Investigative tools that can break into locked phones and search through gigabytes of emails, text messages and other files.

These are pieces of a technology arsenal available to President Trump as he aims to crack down on illegal immigration and carry out the largest deportation operation in American history. To do so, his administration can tap a stockpile of tools built up by Democrats and Republicans that is nearly unmatched in the Western world, according to an analysis by The New York Times.

A review of nearly 15,000 contracts shows that two agencies — Immigration and Customs Enforcement, and Citizen and Immigration Services — have spent $7.8 billion on immigration technologies from 263 companies since 2020.

The contracts, most of which were initiated under the Biden administration, included ones for tools that can rapidly prove family relationships with a DNA test to check whether, say, an adult migrant crossing the border with a minor are related. (Families are often treated differently from individuals.) Other systems compare biometrics against criminal records, alert agents to changes in address, follow cars with license plate readers, and rip and analyze data from phones, hard drives and cars.

The contracts, which ranged in size, were for mundane tech like phone services as well as advanced tools from big and small companies. Palantir, the provider of data-analysis tools that was co-founded by the billionaire Peter Thiel, received more than $1 billion over the past four years. Venntel, a provider of location data, had seven contracts with ICE totaling at least $330,000 between 2018 and 2022.

The Biden administration used many of these technologies for immigration enforcement, including in investigations of drug trafficking, human smuggling and transnational gang activity. How Mr. Trump may apply the tools is unknown, especially as the whereabouts of many immigrants are known and the government faces a shortage of officers and facilities to detain people.

But Mr. Trump has already made clear that his immigration agenda is strikingly different from his predecessor’s. This week, he announced a barrage of executive actions to lock down the borders and expel migrants and those seeking asylum.

“All illegal entry will immediately be halted and we will begin the process of returning millions and millions of criminal aliens back to the places from which they came,” Mr. Trump said at his inauguration on Monday.

Tech products are almost certain to feature in those plans. Thomas Homan, the administration’s border czar, has discussed meeting with tech companies about available tools.

“They’ll certainly use all tools at their disposal, including new tech available to them,” said John Torres, a former acting assistant secretary for ICE.

A White House spokesman declined to comment. ICE said in a statement that it “employs various forms of technology, and information to fulfill its mission, while protecting privacy, and civil rights and liberties in accordance with applicable laws.”

Eric Hysen, the chief information officer for the Homeland Security Department under President Biden, said ICE and other immigration agencies have vast responsibilities. Many tools were designed for investigations of drug traffickers and other criminals, not tracking migrants, he said, while other technology like license plate readers could be used to ease traffic at border crossings.

The federal government has had longstanding internal policies to limit how surveillance tools could be used, but those restrictions can be lifted by a new administration, Mr. Hysen added. “Those are things that can change, but they are not easy to change,” he said.

Creating an arsenal

The buildup of immigration tech goes back to at least the creation of the Homeland Security Department after the Sept. 11, 2001, attacks. Interest in the tools fueled a boom that is expected to grow under Mr. Trump. Leaders in Europe and elsewhere are also investing in the technologies as some adopt increasingly restrictive immigration policies.

Many companies are racing to meet the demand, offering gear to fortify borders and services to track immigrants once they are inside a country.

In the United States, the beneficiaries include the makers of GPS tracking devices, digital forensics tools and data brokers. Palantir and others won contracts with ICE for storing and analyzing data. Thomson Reuters, Lexis Nexis and credit rating companies provide access to databases of personal information that can help government agents find the homes, workplaces and social connections of citizens and noncitizens alike.

Clearview AI, a facial recognition firm, had contracts worth nearly $9 million, according to government records. Cellebrite, an Israeli phone-cracking company, sold ICE about $54 million in investigative tools. The F.B.I. famously used Cellebrite tools in 2016 to unlock the iPhone of a mass shooter in San Bernardino, Calif., to aid the investigation.

Investors have taken note. The stock price of Geo Group, a private prison operator that sells monitoring technology to ICE, has more than doubled since Mr. Trump won November’s election. Cellebrite’s shares have also nearly doubled in the past six months and Palantir’s shares have risen nearly 80 percent.

Tom Hogan, Cellebrite’s interim chief executive, said the company was proud to help “keep our homeland and borders safe with our technology.” Thomson Reuters said in a statement that its technology is used by agencies to support investigations into child exploitation, human trafficking, drug smuggling and transnational gang activity. Lexis Nexis, Clearview and Palantir did not respond to requests for comment.

In an investor call in November, Wayne Calabrese, Geo Group’s chief operating officer, said the company expected the “Trump administration to take a much more expansive approach to monitoring the several millions of individuals” who were going through immigration proceedings but had not been detained.

“We have assured ICE of our capability to rapidly scale up,” he said.

In a statement for this article, Geo Group, based in Boca Raton, Fla., said it looked forward to supporting the Trump administration “as it moves quickly to achieve its announced plans and objectives for securing the country’s borders and enforcing its immigration laws.”

Tracking locations

One technology that may be used immediately in mass deportations can identify the exact location of immigrants, experts said.

About 180,000 undocumented immigrants wear an ankle bracelet with a GPS tracking device, or use an app called SmartLink that requires them to log their whereabouts at least once a day. Made by a Geo Group subsidiary, the technology is used in a program called Alternatives to Detention. The program began in 2004 and expanded during the Biden administration to digitally surveil people instead of holding them in detention centers.

Location data collected through the program has been used in at least one ICE raid, according to a court document reviewed by The Times. In August 2019, during the first Trump administration, government agents followed the location of a woman who was being tracked as part of the program. That helped the agents obtain a search warrant for a chicken processing plant in Mississippi, where raids across the state resulted in the detention of roughly 680 immigrants with uncertain legal status.

Sejal Zota, the legal director of Just Futures Law, a group that opposes government surveillance programs, said the Trump administration would likely need to rely on digital surveillance tools as it would be impossible to physically detain vast numbers of individuals without legal status.

“While this administration wants to scale up detention, and I believe that it will find ways to do that, it will take time,” she said. “I think that this program will continue to remain important as a method to surveil and control people.”

Troves of data

The Trump administration also has access to private databases with biometrics, addresses and criminal records. Agents can obtain records of utility bills for roughly three-quarters of Americans and driver’s licenses for a third of Americans, according to a 2022 study by Georgetown University.

These tools could potentially be used to track people high on ICE’s priority list, like those with a criminal history or people who do not show up for immigration court hearings. Investigators could use the databases to find someone’s automobile information, then use license plate readers to pinpoint their location.

During the first Trump administration, ICE could access driver’s license data through private companies in states like Oregon and Washington, even after the state tried cutting off access to the information to the federal government, according to the Georgetown study.

Mr. Torres, the former ICE official, said this information was critical for agents to find people.

“We know people give false addresses,” he said. Agents can use “big data sharing to triangulate their location based on habits.”

That has raised privacy concerns. “Privacy harms may seem theoretical on paper, but they’re never theoretical for vulnerable people on the front lines,” said Justin Sherman, a distinguished fellow at Georgetown Law’s Center on Privacy and Technology.

During the Biden administration, ICE also bought software from Babel Street, a tech company that gathers data from thousands of publicly available websites and other sources. Its services can assess people as potential security risks based on data. Babel Street did not respond to requests for comment. ICE has also paid about a dozen companies for software that can be used to overcome passcodes, surface deleted files and analyze email inboxes.

Some immigration experts have questioned how much of this technology the Trump administration may use. Some tools are most relevant for targeted investigations, not for widespread deportations, said Dave Maass, the director of investigations at the Electronic Frontier Foundation, a civil liberties group.

“What they are buying and what is actually useful may be totally different things,” said Mr. Maass. Regardless, he said, tech companies “are going to make a lot of money.”

Methodology

The New York Times analyzed government contract data from usaspending.gov. The data covered spending from Immigration and Customs Enforcement and Citizenship and Immigration Services from 2020 to the present. The Times filtered the data to technology-related contracts, using recipient information and contract description. The Times looked at money that had been spent, not just pledged, to calculate the total spending and total number of tech companies.