The ruling ends the 40-year reign at the top by Chicago's Willis Tower.
It's official: New York City's One World Trade Center is now the nation's tallest building, wresting the title from Chicago's Willis Tower, which claimed the top spot for 40 years.
It also leapfrogged the 1,667-foot Taipei 101 in Taiwan to become the third largest building in the world.
Burj Khalifa, the 163-floor office, hotel and residential building in Dubai continues to tower over all the rest in the world at 2,717 feet.
Willis Tower, formerly known as Sears Tower, had threatened to hold onto its top U.S. spot after a design change for the needle on top of the World Trade Center raised the question of whether it was part of the structure or an add-on, like an antenna or lightning rod.
The ruling Tuesday by the Height Committee of the Council on Tall Buildings and Urban Habitat, which is the final arbiter of global building heights, means the WTC building can claim its full 1,776-foot height.
The 1,776 figure is symbolically important for the tower that was built on the site of the Sept. 11, 2001, terror attacks.
The designers of the tower, which is set to open in January, had intended to enclose the needle's communications gear in decorative cladding made of fiberglass and steel. But the developer removed that exterior shell from the design, saying it would be impossible to properly maintain or repair.
Without the needle's extension, the building would have officially stood only 1,368 feet tall, well below the 1,450-foot Willis Tower.
The committee of industry experts, which met behind closed doors in Chicago last week, quickly put any concern to rest on that issue, saying that the structure atop the main building was deemed to be permanent.
"Even though the cladding was taken off the spire, you can still see that it is an architectural element," said Antony Wood, executive director of the Chicago-based council. "It is not just a plain steel mast from which to hang antenna or satellite dishes.
"Conceptually, it is defined, from the architectural point of view, as a major part of the building," he said. "We agreed."
That's not exactly how Chicago's famously combative mayor, Rahm Emanuel, viewed it.
"I just saw the decision," the mayor told reporters. "And I would just say to all the experts gathered in one room, if it looks like an antenna, acts like an antenna, then guess what? It is an antenna. That's number one.
"Number two," he added, "I think (with) the Willis Tower you will have a view that's unprecedented in its beauty, its landscape and its capacity to capture something. Something you can't do from an antenna. Not that I'm competitive. So for all those who want to climb on top of an antenna and take a look, go ahead. I would suggest stay indoors and take a look."
His comments, and the high-profile nature of the announcement -- simultaneous televised news conferences in Chicago and New York City -- reflected the intense rivalry between the two cities, on everything from pizza to architectural style, that dates to the 19th century when Chicago beat out New York City for rights to hold the 1892 World's Fair.
It's hardly surprising that buildings should be front and center, since The Windy City can boast the world's first skyscraper in 1884. Some of the biggest names in architecture -- Frank Lloyd Wright, Louis Sullivan, and Ludwig Mies van der Rohe -- have also made their mark on the city.
But many of the same names -- along with esteemed architects like I.M. Pei -- have also dazzled the public with buildings in New York City, using both cities as showcases for their talents.
The unanimous vote by the height committee, where five of the nine Americans are from Chicago, at least reflected a momentary intra-city truce.
The foreigners come from Australia, Belgium, Canada, China, Denmark, Finland, Germany, Italy, Luxembourg, Qatar, the United Arab Emirates and the United Kingdom.