One World Trade Center, designed by Chicago-based Skidmore, Owings and Merrill, has now reached the 260ft mark.
The planned 104-storey "green" tower is expected to achieve LEED Gold certification and will be the tallest building in the US upon completion.
The completed tower will reach a height of 1,776ft and house 2.6 million square foot of office space, a two-storey observation deck, skyline restaurant, retail spaces, broadcast and antenna masts and four floors for below street-level parking.
The tower is also expected to house the world trade center transportation hub and 9/11 memorial.
The project has been developed by the Port Authority of New York and New Jersey in consultation with structural engineer WSP Cantor Seinuk.
Work on the project began in April 2006 and the tower will reach 50 storeys by the end of 2010, according to businessreviewusa.com.