Jacksonville is about 6 times bigger than Atlanta.

Atlanta (map shows its 114 named neighbourhoods; the area covers the whole city) is approximately 350 sq km, while Jacksonville (map shows its 197 named neighbourhoods; the area covers the whole city) is approximately 1,935 sq km, making Jacksonville 452% larger than Atlanta.
Tip: This to-scale comparison of Atlanta vs. Jacksonville 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.