This is a list of the highest natural points within the 1,569 km2 (606 sq mi) area of Greater London, England. The list includes all 21 peaks at least 100 metres high. One is an isolated hill, at Harrow on the Hill – the other 20 summits are clustered on six ridges (escarpments) in London, four of which extend beyond London and are named: Blackheath Ridge, one of the North Weald Ridges, the North Downs ridge and the Grim's Ditch ridge.