Delineation is the crucial process of defining the geographic boundaries of a Key Biodiversity Area. It is a required step in identifying KBAs that ensures that the site boundaries are ecologically meaningful and practical for conservation management.

The goal of delineation is to map out the specific area that best supports the long-term survival of the key biodiversity elements—such as species or ecosystems—that make the site important. While the boundaries indicate where conservation efforts should focus, they do not prescribe specific management actions.