"whole areas" is correct and usable in written English.
You can use it to refer to a large region or area, such as a country, state, or even a city. For example, "The storm damaged whole areas of the city."
Whole areas of Prague are being blocked off.
But having whole areas taken over is unacceptable, he says.
Whole areas of the team are worryingly undermanned.
There are whole areas taken over by rats.
A consensus closes off whole areas of political debate.
From a young age, there were whole areas of his life he kept to himself.
Across the sub-continent, whole areas are sustained only by remittances.
Whole areas of Caravaggio's life and work remain inaccessible today to even the most meticulous scholarship.
With her innate "eye", she discerned whole areas others had missed or failed to appreciate.
Whole areas of her house have been abandoned because the spirits have taken them over.
There are whole areas of policy where bipartisan consensus remains far out of reach.
