The data comes from RealtyTrac, a real-estate data company. To come up with the rankings, it looked at the median yearly rent for a three-bedroom home in each county and then compared that to the median household income. The rankings were based on how much of that income is spent on rent.
It turns out that in Miami the average family spends 45 percent of their yearly income on rent. The old adage is that people should spend no more than a third of their income on housing and utilities.
Here's a look at the full top ten: Yes, by this measurement, rents are even more unaffordable than in Manhattan (which didn't make the top ten), Los Angeles, and San Francisco. Rents there may be higher, but so are their median incomes.
The study found that it's actually much cheaper to buy a home in Miami-Dade. A mortgage on a similar three-bedroom home would only eat up 34 percent of a family's income — but that's assuming they can put down a 10-percent down payment first.
And even though Miami rents are outrageous, recent data revealed that 65 percent of Miamians live in rentals, an all-time high.