What is the second largest city in the western hemisphere?

By population, the first is Mexico City, Mexico (20,450,000 people), and the second is New York City, US (19,750,000 people).

By area, New York City is the first (6,905 square miles) and Buenos Aires, Argentina is the second (4,203.8 square miles).

Info from http://en.wikipedia.org/wiki/List_of_metropolitan_areas_by_population.

These answers are incorrest.

NY City population is a lillte over 8 million.

The area is only 300 sq miles -- LA ia much bigger;

so is Oklahoma City.

What they are talking about are Metropolitan areas.

For NY this includes parts of New Jersey and CT,

as well as Westchester and Nassau counties.

This is not New York City.