Actually, I think all the people on earth in a city with the population density of New York City, would fit in the state of Texas. Source, here, among others:All the people living on this earth standing shoulder to shoulder, would fit inside the city limits of Jacksonville Florida.
If Everyone Lived Like New Yorkers, The Population Could Fit Into Texas
New info-graphic from Per Square Mile shows that if the world lived like New Yorkers, we'd all fit into Texas.
www.refinery29.com