"We call them 'midnight regulations.' It's the last chance to put these rules on the books before the Trump administration changes to the Biden administration," said ProPublica investigative reporter Isaac Arnsdorf who has created an online database tracking the pending regulations for the nonprofit news site. "They can be reversed, but not easily."
They include religious exemptions for federal contractors under employment discrimination laws; looser water efficiency standards for shower heads and washing machines; and stricter eligibility for food stamps, even as millions out of work in the pandemic look to the government for help.
"The final days of an administration are obviously hugely important, and it's just natural to want to get things done," said Carol Browner, former EPA administrator during all eight years of the Clinton administration and also a former member of President Barack Obama's transition team and first climate czar.
"But you're not free to just do it willy nilly. There's the law, there's the science, there's the process," Browner said.
Experts said the raw number of 11th-hour regulatory changes appears, so far, to be on par with what occurred during the final weeks of the Obama administration. But some policy advocates and independent watchdogs worry the rushed process will compromise legality and public safety.
Many of the most significant last-minute regulations are focused on environmental and scientific policy, including a controversial effort to ban EPA use of any scientific study that doesn't fully disclose all of the underlying raw data. Its defenders call it a step toward transparency, while critics call it censorship.
Studies on the impact of pollution on human life, for example, often rely on sensitive personal medical data, which patients don't want publicly disclosed.
"You will simply not get the quality of science that EPA needs to make decisions, and this is a very, very intentional move on their part, on behalf of polluters, which is to limit the science and therefore limit the ability of EPA to make the smartest decision," said Browner.
The Trump administration is also racing to auction off drilling rights in the Arctic National Wildlife Refuge -- a move strongly opposed by Biden -- with an aim of making it much more difficult for the next administration to turn back from expanded oil and gas development.
"The degree to which the leases have been entered into you might have to buy them back," said Browner. "But hopefully the reality is we can continue to protect these areas that have been protected for hundreds of years now."
The president is also attempting to further cement his crackdown on immigration. In his final weeks, he's added eight new questions to the citizenship test and tried to make it harder for high-skilled foreign workers to get visas.
"In this last-minute rush before the inauguration the Trump administration is doing everything they can to bring legal immigration closer and closer to the bare minimum," said Ali Noorani, president and CEO of the National Immigration Forum, a nonpartisan advocacy group. "It is ramping up enforcement actions, and really trying to do everything they can to finish checking those boxes and make it as hard as possible for the Biden administration to rebuild the nation's immigration system."
On foreign policy, Trump is abruptly and sharply reducing the number of U.S. troops in Iraq and Afghanistan, with no more than 2,500 American service members expected in each country by the end of the year. While the pullout was a key 2016 campaign promise, experts said the late move puts Biden in the difficult spot of needing to decide whether to redeploy troops back into theater early in his first term.
Outgoing former President George W. Bush, in a similar situation, notably deferred to his successor, Obama, in late 2008 on whether to approve a troop surge in Afghanistan.
Trump has also taken steps to formally shut the door on a two-decade-old treaty he has long criticized, pulling out of the "Open Skies Treaty" last month which had allowed U.S. and Russia to conduct mutual surveillance flights to build trust. Critics say the move is a gift to Russian President Vladimir Putin.
"Russia didn't adhere to the treaty, so until they adhere, we will pull out," Trump said in May.
"The problem is if we don't abide by our own treaties, if we don't recognize and support our own treaties, then who in the international community is going to want to partner with us in the future?" said retired Adm. Bill McCraven, who oversaw the raid to kill Osama bin Laden in 2011.
Some of Trump's final executive actions will have permanent impact.
The Justice Department is rushing to execute as many federal death row inmates as possible before Biden has a chance to reimpose a death penalty moratorium.
Eight federal inmates have been executed so far this year -- the most in more than a century -- with five more slated for death before Inauguration Day next month.
"The pace of these federal executions has no historical precedent," said Robert Dunham, executive director of the independent, nonpartisan Death Penalty Information Center. "The last time more than one person was executed during a transition period takes us back to Grover Cleveland's first presidency in the end of the 1880s."
The Trump administration, in a late-term rule change, is also giving executioners greater flexibility in how they kill.
"The regulation will allow them, without challenge, to use whatever method of lethal injection that it wants to use," Dunham said.
Meanwhile, Trump continues with a record number of lifetime appointments to federal courts, breaking with 123 years of precedent by pursuing Senate confirmation of even more judges after losing reelection.
"Generally once an election occurs, confirmations stop until the next Congress," said Gabe Roth, executive director of Fix the Court, an independent judicial watchdog. "It's hard to know the impact right now exactly that these Trump-appointed judges will have, but we know it's going to be big, it's going to be huge, it's going to be generational."
Some of Trump's final acts face challenges in court, and if Democrats win control of the Senate, there could be fast-track repeals of recently finalized regulations. But experts say most of the policy changes won't be easily undone.
"You have to go through the whole rule-making process all over again, which takes multiple years and a lot of resources and is cumbersome by design," said Arnsdorf.
The process is a reminder that the power of the presidency can make a lasting impact on America up to the very last minute of a White House transition.