Ohio is about 28 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 Ohio is approximately 106,056 sq km, making Ohio 2,684% larger than Sydney.
Tip: This to-scale comparison of Sydney vs. Ohio uses the Mercator projection, which distorts the size of regions near the poles.
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