Official city boundaries are a useless way to identify urban places. Some cities, like
Jacksonville have official boundaries that extend way out into the countryside, effectively including both "the city" and "the suburbs" within the official city limits. Other cities, like
Boston, have tiny official boundaries and "suburbs" that are functionally part of the region's urban core.
So let's play a little game: Throw out the official boundaries, and make up more sensible places to draw the line between "city" and "suburb" for your metropolis. You can decide whatever you want, just explain it to us. If you can,
USE THIS publicly editable google map to illustrate. Pick your city and draw the boundaries using that link.