Jacksonville is about 8 times bigger than Des Moines.

Des Moines (map shows its 58 named neighbourhoods; the area covers the whole city) is approximately 228 sq km, while Jacksonville (map shows its 197 named neighbourhoods; the area covers the whole city) is approximately 1,935 sq km, making Jacksonville 748% larger than Des Moines.
Tip: This to-scale comparison of Des Moines 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.