We know because the Yanks keep telling us so.
Just leafing through one of those catalogues of everything no modern home can do without. (Like a battery operated corkscrew cleaner.)
One item on offer is the complete series of Bonanza on DVDs. The (fictional) ranch was supposedly the biggest in the US of A: a thousand square miles.
Anna Creek Station in South Australia is 9,140 sq m.
Australia has 53 stations over TWO thousand sq m.
Reminds me of the old joke about the Yank on a bus tour with a bunch of international tourists.
He boasts, “Why, my ranch is so big, I can drive from sunup to sundown and still be on my own land!”
An Indian gentleman replies gently, “Ah, yes. I too once had a car like that.”