The Port Authority is headquartered at 4 World Trade Center in Lower Manhattan. The agency was headquartered at 1 World Trade Center in the first World Trade Center complex, where it occupied of space. It had been headquartered in the WTC complex beginning in 1973. After the previous headquarters were destroyed in the September 11, 2001 attacks, the Port Authority moved into 225 Park Avenue South in Midtown Manhattan, with employees divided between offices in New York and New Jersey, before returning to the World Trade Center in 2015.