The phrase 'a single area' is correct and can be used in written English.
It can be used to refer to one specific area or location. For example, "The business focussed its resources in a single area of the city."
"Hunter-gatherers, with their reliance on a single area, are profoundly settled," Mr. Brody writes.
This will be piloted in a single area," the spokesman for the deputy prime minister said.
This will be piloted in a single area," said a Liberal Democrat spokesman.
There is no technical need to have all the terminals and computers in a single area.
Treatment of movement disorders through deep brain stimulation, for example, usually targets a single area.
Nominations focused on a single area or a combination of areas of excellence will be considered.
A program of 27 units in a single area of specialization must be completed.
If a bar is labelled 'single origin', it's made from beans from a single area.
It's hard to pinpoint a single area where Yahoo outperforms another website or app.
Thus, with 10 anole species in a single area, each has its own characteristic microhabitat.
In the past, pollsters and politicians had elided the two issues – considering "race/immigration" as a single area of concern.
