A conservation area is one that has special architectural or historic interest.
Usually these areas are characterised by buildings with strong group value, created by consistent use of traditional forms and materials. Very often the areas include listed buildings, individually protected for their special historic or architectural interest. The high visual quality of these areas is often enhanced by mature trees and boundary walls.
You can find more information on Conservation Areas on the English Heritage website.
There are 18 conservation areas in Barnsley:
Conservation Area Map