San Bernardino is about 6 times bigger than Sydney.

Sydney is approximately 27 sq km, while San Bernardino (map shows its 50 named neighbourhoods; the area covers the whole city) is approximately 161 sq km, making San Bernardino 502% larger than Sydney.
Tip: This to-scale comparison of Sydney vs. San Bernardino uses the Mercator projection, which distorts the size of regions near the poles.
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