Boise is about 3.5 times bigger than Newark.

Newark (map shows its 20 named neighbourhoods; the area covers the whole city) is approximately 63 sq km, while Boise is approximately 221 sq km, making Boise 253% larger than Newark.
Tip: This to-scale comparison of Newark vs. Boise 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.