Canberra is about 23 times bigger than Rockville.

Rockville (map shows its 87 named neighbourhoods; the area covers the whole city) is approximately 35 sq km, while Canberra is approximately 814 sq km, making Canberra 2,217% larger than Rockville.
Tip: This to-scale comparison of Rockville vs. Canberra 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.