Coulsdon is a settlement now situated at the south of the London Borough of Croydon, lying between approximately 12.5 and 13 miles from Charing Cross (a point of measurement for the centre of Greater London). It is surrounded by the Metropolitan Green Belt of Farthing Downs, Coulsdon Common and Kenley Common and two smaller settlements contiguous to it, Woodmansterne and Reedham, Purley.
Modern Coulsdon comprises Old Coulsdon and Smitham Bottom, which grew substantially with the early arrival of the railway — this has a branch diverging here and so Coulsdon has three stations serving its communities. Coulsdon encompasses several dry valleys (with natural underground drainage) due to its highly permeable soil — these underground headwater streams converge and spring at a surface, north in Croydon as the River Wandle. The London Loop path passes directly through the centre of the district.