Chicago is about 2.5 times smaller than Mexico City.

Mexico City is approximately 1,485 sq km, while Chicago is approximately 590 sq km, making Chicago 39.72% the size of Mexico City.
Tip: This to-scale comparison of Mexico City vs. Chicago uses the Mercator projection, which distorts the size of regions near the poles.
Our free app, MapSize by MyLifeElsewhere — compare any two places, to scale on your mobile device.