Is there a limit to the number of tiles a city can use in Civ 5?
Up to 3 hexes away, 36 hexes total
Plus one more for the hex the city is on.
All of the previous games in the Civilization Series used squares for the grid, and the maximum city radius was 2ish squares away. Take a look at the image below for what I mean by 2ish. (In words, the exact city radius is a 3x3 grid centered on the city, with one square from each corner removed.) That was a total of 20 squares, plus one more for the city square.
Civilization 4, and earlier
I'm guessing this is where the "you should have a 20 pop city" advice comes from?
Below someone implies that you can go up to 5 hexes in your capital or other situations? I want a luxury resource that is 4 hexes away - in my capital. Will I ever be able to buy or reach it?
@niico Your borders can stretch 2 hexes beyond this. But your population won't work the hex. IE: You'll get the happiness from the luxury, but not the $$.