Spaceports (Tertium Millennium)

Spaceports are prominent trade outposts, supervising trade between countries on Earth and their extraterrestrial colonies. While much of the population is the crew manning them, there usually is a significant citizen population on board too.

New New York (US)
New New York is a prominent spaceport, supervising trade between the United States of America, the Apollo Territory on the Moon/Luna, and American Mars. A total of 1.5 Million people lived there by 2400. It was set up in the 22nd Century.