When you need to describe a concentrated or specialized zone, there are plenty of synonyms for the phrase "focused area." Some other ways to express this concept might include "targeted region," "specific zone," "centralized locale," "narrowed scope," "designated vicinity," "concentrated realm," "restricted field," "restricted space," "intensive zone," or "selective section." Depending on the context and the level of specificity required, any of these terms could be a good fit to describe a particular area or zone that receives focused attention and scrutiny.