If a couple were trying to choose the most ostentatious and logistically complex time and site for a wedding celebration, it might be Madison Square Garden in Manhattan over the Fourth of July weekend.

The streets are packed with visitors vying to see the fireworks show near the Statue of Liberty. Even more crowds are arriving this year to mark the nation’s 250th birthday and to attend World Cup soccer matches.

Yet the global pop star Taylor Swift appears poised to embrace the chaos.

Ms. Swift and her fiancé, Travis Kelce, the Kansas City Chiefs tight end, have rented Madison Square Garden for two events on Thursday and Friday tied to their nuptials.

The occasion could eclipse the Met Gala as the cultural event of the year, with scores of celebrity guests arriving in their finest black-tie attire — and hundreds of her loyal fans assembling outside to bask in the joy surrounding the occasion.

Behind the scenes, a complex logistical blitz has been unfolding with military-like precision for weeks.

The list of tasks was daunting: hiring private security, filing permits to close streets, organizing lodging and transportation for a phalanx of A-listers, bringing in decorations for the cavernous arena and coordinating with the city over having police officers available for crowd control. All this while trying to keep the event a secret.

In the final days, some details were revealed, including an internal police memo listing the run of show for what it described as the “Taylor Swift Wedding” that was expected to end at 2 a.m. on Saturday. Hundreds of officers are expected to patrol the area.

Camille Joseph Varlack, a former deputy mayor to Mayor Eric Adams who staged major events, said that it was important for Ms. Swift to coordinate with city agencies.

“To drop an event like this in the middle of an already busy summer is challenging,” Ms. Varlack said.

While some fans were disappointed at the idea that Ms. Swift would get married at a sports arena, Ms. Varlack said it made sense in terms of security and privacy and compared an event at the Garden to being “encased in a fortress.”

“It’s definitely easier than if she wanted to get married in Central Park,” she said.

Still, there will be logistical challenges getting the roughly 1,000 guests who are expected on Friday into the venue and making sure that fans outside stay safe in temperatures that could soar to more than 100 degrees.

Members of the Kansas City Chiefs football team have booked rooms at the Marriott Marquis hotel in Times Square, and guests are expected to enter the Garden through a large tent at the V.I.P. entrance on 31st Street. The police memo said that 500 vehicles were expected.

The Garden has seen a flurry of activity this week. Large trucks delivered tree decorations and boxes of lobster, and a red carpet appeared on a staircase before being removed.

Some fans consider the Garden, which opened in 1968, drab. But Ms. Swift is expected to craft elaborate decorations, much like her dramatic sets on her tours.

Sonal J. Shah, a luxury wedding planner in New York City, said that security had most likely ended up being Ms. Swift’s greatest concern — and one of the largest budget items.

“It is a controlled environment and a blank canvas,” she said of the Garden. “The couple can do whatever they want with it.”

Ms. Shah said that street closures were not without precedent and that she had staged a “groom’s procession” in Columbus Circle in Manhattan and obtained permits for “rolling street closures.” If the event has 1,000 guests as expected, Ms. Shah said the greatest challenge would be “to impress that many guests.”

“The food, the alcohol, the entertainment — those are huge expenses, and they will want to knock it out the park,” she said.

José Maldonado, the president of the union that represents workers at the Garden, said that an event at the arena with 20,000 people typically requires more than 800 workers. A smaller event with 1,000 guests might require about 250 workers.

Lexi Denihan, the creative director of Hamptons Aristocrat, a luxury culinary event company, who has worked on more than 500 weddings, said that more than 125 catering workers would be needed. The rule is one server per eight guests.

One of the greatest challenges, she said, is coordinating the arrival of vendors and equipment in Manhattan, including the 8,000 glasses required for a six-hour event.

“It’s an orchestra — the draping, the sound equipment, and someone is going to get stuck in traffic,” she said.

The boxes of lobster, she said, were “a very New England thing to do” and “the most luxury protein out there besides Wagyu.”

Private security is another challenge, Ms. Denihan said, and celebrities often arrive at events with their own security details. The staff must check bags and keep out phones while looking for troublemakers and making sure the couple is protected.

In early June, Winick Productions, a prominent event planning company based in New York, filed an application to close streets near the arena with the city’s Street Activity Permit Office.

The Garden complex is a labyrinth with a five-story circular ramp leading to the arena floor. The playing surface — ice for hockey, hardwood for basketball — is on the fifth floor, above Penn Station and a theater used for shows and concerts.

The ramp is narrow, but it can fit luxury cars. Larger trucks park outside, and forklifts are used to transport items up the ramp. The arena is windowless, and the couple can control images from the event without worrying about drones.

While many wealthy New Yorkers leave the city for the Hamptons and the Jersey Shore over the Fourth of July weekend, others stay to enjoy the fireworks show from their rooftops or flock to viewing parties along the rivers.

The year’s celebrations are expected to be larger than usual. On Friday, there will be a benefit show in Times Square as part of President Trump’s “America250” program at which the ball will drop eight times to mark midnight in every American time zone. Tall ships and war vessels will also begin to sail into the city, carrying 20,000 sailors, much more than during Fleet Week.

On Saturday, there will be a major fireworks show in Lower Manhattan on the East River and the Hudson River. On Sunday, there is a FIFA World Cup match in New Jersey between Brazil and Norway, and fans have hit the streets of Manhattan to catch trains at Penn Station beneath the arena.

Mayor Zohran Mamdani has hinted at the nuptials but has not confirmed any details. On Tuesday, he raised another benefit of the Garden at a news conference related to the heat wave: strong air-conditioning.

“My recommendation to all New Yorkers is to stay inside and stay cool,” he said. “And if you happen to be getting married at Madison Square Garden, you will be staying inside, and you will be staying cool.”

Maria Cramer and Tim Balk contributed reporting.