President Trump is set to take in an MMA bout Saturday night at Madison Square Garden — and stay in the city into Marathon Sunday, potentially putting Midtown traffic into a chokehold, according to a law-enforcement source.

Trump is scheduled to be in attendance when the Mecca plays host to UFC 244, headlined by a five-round tangle between welterweights Nate Diaz and Jorge Masvidal, a New York Times reporter tweeted on Tuesday, a source told The Post.

“They’re making plans for him to sit in the seats,” said the law-enforcement insider, who advised attendees to arrive early for stringent security screenings.

Trump’s tentative Saturday night plans were first detailed in a tweet by a New York Times reporter, citing sources.

In 2016, the then-president-elect was invited by UFC president Dana White to a fight at the Garden, but ultimately decided not to go on the advice of his Secret Service handlers.

Following the contest, the president will crash at Trump Tower into Sunday, the source said — when the New York City Marathon was already set to snarl traffic across the Big Apple.

He’s tentatively scheduled to depart the city later that day, though it wasn’t immediately known whether he would leave before or after the race kicks off.

There are still tickets to UFC 244 available at Ticketmaster — and it can also be purchased to stream on ESPN+.