The map above confirms it, showing the economic output of America's largest metropolitan areas rivals countries as large as Argentina and Canada. Prepared by Zara Matheson of the Martin Prosperity Institute, it's based on data compiled for the U.S. Conference of Mayors and The Council for the New American City annual U.S. Metro Economies Report.
Even in crisis, our strongest cities perform the economic function of small (or sometimes, not so small) nations. If they were countries, U.S. metros would represent 37 of the world's largest economies, as I noted in an earlier post. This slideshow lists the largest U.S. metros and the countries to which they best compare.