The seat comprises the South-Western portion of Lewisham borough with the northwestern tip of Bromley borough. At the heart of the seat is Forest Hill, bisected by the route of the South Circular Road. Its ambit also includes some of the Crystal Palace hill (the park and site of the palace itself is on the intersection of five boroughs) and the nearby areas of Anerley, Penge and Sydenham.The Guardian however positively summarised it in 2010 as "suburban south-east London, with a large Afro-Caribbean population."
To create the new constituency the Boundary Commission for England transferred Perry Vale ward, Bellingham ward, Forest Hill ward, and Sydenham ward from the former Lewisham West constituency. Clock House ward, Crystal Palace ward, and Penge and Cator ward were transferred from Beckenham constituency.