New Jersey is about 5 times bigger than Sydney.

Sydney (the 30 councils of metropolitan Sydney, without the Blue Mountains, Hawkesbury, Wollondilly and the Central Coast) is approximately 3,810 sq km, while New Jersey is approximately 19,211 sq km, making New Jersey 404% larger than Sydney.
Tip: This to-scale comparison of Sydney vs. New Jersey uses the Mercator projection, which distorts the size of regions near the poles.
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