Bronx is around the same size as Ulm.

Ulm (map shows its 55 named neighbourhoods; the area covers the whole city) is approximately 119 sq km, while Bronx is approximately 109 sq km, making Bronx 92.04% the size of Ulm.
Tip: This to-scale comparison of Ulm vs. Bronx 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.