High Topps is a high, fell area, to the west of the Lake, above the upper reaches of the Valley of the Amazon, close to Kanchenjunga and its spurs, Grey Screes and Ling Scar. It is the main location for the action in Pigeon Post and also features in The Picts and the Martyrs.
It is a whacking big place full of old mine workings. Slater Bob tells them about ... names like we call ‘em, Grey Cap and Slate Crop, and Brown’s Dog, and Jimson’s, and Giftie and the rest .... but I couldn’t make nowt o’ his numbers (on the young Government chap’s map) .... there’s many a score of those old workings on High Topps (PP3). It was amongst these workings that the prospectors found 'Golden Gulch'.
- Greenbanks ... we were up there yesterday. High Topps ends just about there (PP7)
The Great Wall is a rock on the edge of the Topps from which Nancy checks for Squashy Hat: she was standing up, on the top of the rock, which, by this time, they had agreed to call The Great Wall (PP10). Beyond the hollow of the Gulch Roger could see far away to the edge of the Topps, and the Great Wall, and the uppermost branches of the Look-out Tree above the hidden camp (PP19). See image of the Great Wall: Great Wall
An area to the north of Coniston Water, called Yewdale Fell, near Tilberthwaite, bears a lot of similarities to High Topps, and Arthur Ransome visited the area as part of his research for writing Pigeon Post.