Newark is about 3.5 times smaller than Boise.

Boise is approximately 221 sq km, while Newark (map shows its 20 named neighbourhoods; the area covers the whole city) is approximately 63 sq km, making Newark 28.35% the size of Boise.
Tip: This to-scale comparison of Boise vs. Newark uses the Mercator projection, which distorts the size of regions near the poles.
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