The Chalk

The Chalk's most known land mark is the 'White Horse'. The Chalk's 'White Horse' is not unlike the Roundworld's Uffington White Horse, situated on the upper slopes of White Horse Hill in the English civil parish of Uffington, (in the county of Oxfordshire, historically Berkshire.)
There are villages, such as Twoshirts, but these appear to be on the borders of the Chalk and serve as points for entry and exit. Every so often, a herd is assembled for sale and slaughter, and drovers such as Seth Petty lead it on foot to faraway Ankh-Morpork. These days, the Chalk is now served by rail: a main line out of the city stops at Twoshirts. It remains to be seen what this will do to the droving trade.
The region is a feudal autocracy. Most of the land is owned and all of it ruled by the Barons de Chumsfanleigh (pronounced Chuffley - it's not their fault, they were born with it - cf. the English 'Marquess of Cholmondeley', pronounced 'Chumley'). They became barons by cutting off the heads of other people who thought they owned it, but those were in far off days and now they own it not because of swords but because of owning the right piece of paper stating that they do. Roland, who in the first three books of the series is heir to the Baronacy, has what is normally a red-with-embarrassment, full-of-awkward-silences relationship with Tiffany Aching. He becomes Baron in the fourth, and marries Letitia.
Tiffany provided nursing care to the old Baron during his final illness and heard his last testament before he died. The old Baron recalls the informal arrangement he had with Granny Aching, by which she would act as the check and balance on his absolute rulership of the Chalk, generally by giving him a damn swift and hard kick up the arse if she thought he was getting it seriously wrong. The outgoing Baron then charged Tiffany with keeping their joint family tradition going by being prepared to do exactly the same for Roland if she ever felt he needed advice or grounding.
With government working at the Baron's pleasure, and physical separation of the populace preventing local co-operation, there is very little organised society. Life goes on in very small groups, families or a few neighbours. The conclusion of I Shall Wear Midnight suggests improvements in governance and organisation are under way. Tiffany is owed a few favors by the Chumsfanleighs, and instead of the fifteen gold pieces offered by the old Baron, she extracts promises for a school (which she has already begun), apprenticeships and scholarships and a hospital to be supervised by Preston when he is trained by Dr Lawn.

Geography

The name is not fanciful. Fathoms of chalk that once settled from an ancient sea underlie the thin turf. The locals say that in those days the creator made animals out of stone; sometimes they find one. Buried randomly in the chalk are lumps of flint, only fist to football- sized, resulting from some igneous or magical disaster during its formation. (Or possibly driven into the chalk very forcefully in some more recent Wizards' war.)

Natural Resources

The thin turf, with almost no subsoil, supports sheep and little else. Wool, cheese, lamb and mutton support a scattered population of family sheep ranches (although these are likely to be owned, feudally, by the local Liege).
Magic isn't a common topic on The Chalk. Oh, the world still runs on magic, and the effects are still seen, but the shepherds seem resigned, and they concern themselves with the the shearing or the lambing, according to the season. Witches appear, as elsewhere, but they adapt to the sparse population mixed with the Nac Mac Feegle. They are charged more with the care of the land and the sheep than the few humans, and they advise the Pictsies. The Pictsies depend on a hag, as they call a witch, for their rare interaction with humans. They have their own appropriate magic, and don't ask much but advice from the witch. The practice of anything called witchcraft is prohibited by the Baron and old custom. This is largely ignored these days, but anything too showy or blatant - such as Tiffany's employment of the Feegle, Sorcerer's Apprentice style, to clean Mrs Petty's slovenly and ill-kept cottage - will attract negative attention, even in these liberally-minded times.
Witches have to do what needs to be done, and on the Chalk, that's more likely to do with sheep or Feegles than people. They're there, just the same, just in case.

Type

Grassland

Location under

Discworld

Owner/Ruler

Barons de Chumsfanleigh