It will be Trump's first visit to India as president and will make him the fourth consecutive American leader to make the passage to India.
Here are five things to watch:
You've got a friend in me
Trump's visit to India will be a symbolic display of friendship between the United States and India, and will include a heavy dose of pomp and ceremony. The president will be welcomed to India with a mega rally, visit to the Taj Mahal, and be honored with a state dinner.
"In some ways, American presidents, go to India to feel loved," said Tanvi Madan, an expert on India at the Brookings Institution.
When the president arrives, the crowd-size-counting president is expected to address more than 100,000 people alongside India's Prime Minister Narendra Modi for a welcome rally that's been dubbed "Namaste Trump," which translates to "Greetings Trump." Tens of thousands more are expected to line the streets of the presidential motorcade route.
Before leaving on Sunday, Trump told reporters at the White House that he heard it was going to be a big event.
"Some people say the biggest event they've ever had in India," he said. "That's what the prime minister told me."
Modi is in a sense returning the favor after Trump hosted him for a "Howdy Modi" rally in Houston last year before an audience of some 50,000 people, many of them Indian American. During the Houston rally, Trump declared Modi "one of America's greatest, most-devoted and most-loyal friends."
While Trump appears to enjoy a level of popularity in India relative to some other close U.S. allies, Madan noted that it's the norm for all U.S. presidents -- popular or not -- to get elaborate and boisterous welcomes in India.
"Even President (George W.) Bush, who was not considered to be very popular around the world. He went to India towards the end of his administration. He was getting criticized by U.S. allies in other places. His popularity rating was very high, and it really ratings very high in India, and Prime Minister Manmohan Singh, then kind of hugged him and told him that you know all of India, loves you," Madan said.
Trade deal and other agreements
Trump has long teased a trade deal with India, but so far, such an agreement has remained elusive. Days before heading to India, the president appeared to moderate expectations around the potential for a trade truce.
"We can have a trade deal with India, but I'm really saving the big deal for later on. We're doing a very big trade deal with India. We'll have it. I don't know if it'll be done before the election, but we'll have a very big deal with India," Trump told reporters on Feb. 18.
Trade tensions between the two close trading partners first cropped up when the U.S. imposed higher duties on aluminum and steel imports and later removed India's beneficiary trading designation. India, in retaliation, has imposed tariffs on some U.S. products.
Despite speculation in recent weeks that a deal could come together, a senior Trump administration official said Friday "we're not quite there yet" as the U.S. seeks certain concessions from India in exchange for reinstating India's preferential designation, among other issues. The official said the ball is in India's court.
"What we see is an increase in barriers, not a decrease, this will certainly come up among the leaders," the official said. "Whether or not there will be an announcement on a trade package is, really, wholly dependent upon what the Indians are prepared to do."
Still, the official described the trading relationship as "critically important" and said the two sides continue to engage in trade talks. But perhaps the clearest indication of where negotiations stand, two of the president's top officials on trade -- U.S. Trade Representative Robert Lighthizer and Treasury Secretary Steven Mnuchin -- are not part of the presidential delegation on the trip.
Rick Rossow of the Center for Strategic and International Studies floated the possibility that the two leaders could still announce broad principles of an agreement as a demonstration of progress even as a final deal continues to be worked out.
"I suspect that, ultimately, with this much high-level attention, you'll see something come out of this, even if it's language which notes that, you know, some T's have to be crossed at a later date, and some I's have to be dotted," said Rossow.
The president has repeatedly expressed his eagerness to serve as a mediator in the volatile, decades-long conflict between India and Pakistan over Kashmir, pointing to past experience that he said he has arbitrating "some pretty big ones -- from friends."
"I would be willing to help if both wanted. If both Pakistan, let's say, and India wanted me to do that, I am ready, willing and able," Trump said during a bilateral meeting with Pakistan's Prime Minister Imran Khan in September.
While Pakistan is eager to accept the president's entree into the matter to internationalize negotiations, India has rebuffed the offer and wants to keep Kashmir as a bilateral issue.
Asked whether Trump will again seek to insert himself in the conflict on this trip, a senior official didn't offer a direct response.
"I think what you'll hear from the president is very much encouraging a reduction in tensions between India and Pakistan, encouraging the two countries to engage in bilateral dialogue with each other to resolve their differences," the official said, without addressing whether the president continues to see a role for himself in facilitating any such dialogue.
Bruce Riedel of the Brookings Institution said the administration has "no practical plan for mediating between India and Pakistan on Kashmir" and notes that past presidential offers to mediate have fallen flat.
"In 1999, President (Bill) Clinton, briefly, flirted with the idea of mediation, and the Indians shut it down almost immediately," Riedel said.
Though there's no predicting whether Trump will refrain from commenting on the conflict, Richard Rossow of CSIS said the Indians would certainly prefer he didn't.
"You never exactly know what the president, if he's speaking off the cuff, may bring up. A number of times he's talked about trying to intervene in the Kashmir dispute. And that certainly is something that India wouldn't want to see on the public stage during his visit there," Reidel said.
The word "China" likely won't appear in any official statements or agreements during the trip, but countering the rise of an ascendant China has been -- and continues to be -- a cornerstone objective in strengthening the U.S.-Indian strategic alliance.
"I don't suspect (China) will be brought up publicly that visibly. I think it will be discussed behind the scenes for sure," said Rossow, who notes that there are shared concerns across a range of issues, from trade to military cooperation. "So, it drives a lot of what's happening, but a lot of times it's not so visible above the water -- more so behind the scenes."
Madan anticipates that the U.S. and India will announce some defense cooperation deals in conjunction with the visit, as it relates to Indian purchases of U.S. military aircraft and equipment.
"So while you might not hear the word China mentioned, you will hear allusions to it constantly throughout remarks, and some of the deals you will see, I think you will see some defense deals around the visit, and perhaps, put into some of the joint statements and President Trump will no doubt, take credit for them," Madan said.
India's citizenship law
Just as serious discussion about China is not expected to play out in full view, so too is any discussion of India's controversial new citizenship law expected to remain behind closed doors.
The new law provides a fast-track to citizenship for migrants from certain bordering nations who have fled religious persecution; but it excludes Muslims. The law has been decried by critics as an affront on religious tolerance and has sparked fierce protests within India over the last couple of months.
Asked if the president plans to speak out against the law during his visit, a senior Trump administration official said the president will focus on shared U.S.-Indian values in his public remarks but will almost certainly raise concern with Modi behind closed doors.
"Certainly in private, he will raise these issues, particularly the religious freedom issue, which is extremely important to this administration," the official said. "This is something that is important to the president and I'm sure it will come up."