The village of Helm St Mary is near the castle; the village green begins just outside the castle gates.
The nearest train station is at Bowbridge, ten minutes away by car.
The entire castle and its grounds is covered in a web of protective spells. Visitors often find that this gives the place a restful atmosphere (or a stifling one, depending on their frame of mind).
The castle itself is on a hill, and is in two parts. The older part is grey and turretted; the walls are three feet thick, and the interior walls are whitewashed stone. The newer extension has a spread of big windows, and a flag flies from the roof.
A long tree-lined avenue leads from the gate to a gravel sweep in front of the great door of the old part of the castle.
The main entrance hall is a lofty space with a glass dome high overhead. There is an enormous chandelier suspended from the dome. A majestic pink marble staircase leads up to a gallery with a curly marble balustrade, and various stately panelled doors with statues over them lead off into other parts of the building. In addition to the grand front door, there is a pentagram of white tile built into the floor that allows less mundane means of entrance and exit.
The library is large, and appears to contain thousands of books - and contains ten times more than it appears to contain, with spells set up to move the books in and out of the visible shelf space. Among the books there are some imported from other worlds, including the school stories of Angela Brazil. In Gabriel de Witt's day, the librarian is a Mr Wilkinson.
The dining room contains a long table, where all of Chrestomanci's staff eat together. There is a grand cabinet with valuable antique porcelain on display in it. There is a row of long windows down one side of the room, with orange curtains.
Other rooms include the Large Drawing Room, the Middle Drawing Room, the Little Drawing Room (which is seventy feet square), the Large Saloon, the Middle Saloon, and the Small Saloon. The Middle Drawing Room is large, and contains gilded armchairs. Guests are sometimes received in the Small Saloon, which has pictures on the walls and is rigged with listening spells (as are the other rooms, probably).
The castle is surrounded by formal gardens and smooth lawns, with oak and cedar trees and laurel bushes. Rooks nest in some of the trees.
There is another, even older, castle ruin on the grounds, on another hill with a steep path leading up to it (which turns into a steep staircase running up the side of the high wall that surrounds the ruin). It is surrounded by misdirection spells - or perhaps actually moves - and only Chrestomanci (or people he has invited, under his supervision) are allowed to farther than the base of the staircase. (see Charmed Life (spoilers))
In Gabriel de Witt's day, the office of Chrestomanci was at the head of the great staircase, behind a black-painted door. The room was oval-shaped and panelled in dark brown wood, with brown carpet on the floor and no furniture apart from a large dark desk. It had at least six windows, in a high curving row near the ceiling. The wall panels could be rolled back to connect it with the offices on either side. Gabriel de Witt made his employees dress in formal sober clothing - black or grey suits with shining white cuffs and collars for the men, black or grey dresses with neat black lace mittens for the women.
Gabriel de Witt's staff included Miss Rosalie, Mordecai Roberts, Frederick Parkinson, Flavian Temple, Dr Simonson, Mr Wilkinson, and two sorceresses named Beryl and Yolande, who do secretarial work and whom Christopher can't tell apart. The Castle's domestic staff of the time included a butler, a housekeeper, two chefs and various under-cooks, various footmen, various maids (including three called Erica, Bertha, and Sally), and a boot-boy named Jason. The grounds staff included various gardeners (led by a Mr. McLintock), stableboys, etc.
During Christopher Chant's childhood, there was a training scheme for young enchanters set up at the castle (partly so that there would be people to keep Christopher company). Apart from Christopher himself, students included Jason, the girl who would become Tonino Montana's mother, and Christopher's future wife Millie.
Christopher's staff include Michael Saunders, Bernard, an old lady in lace mittens (presumably a carry-over from Gabriel De Witt's staff), and at least two each of younger men and younger women. He is on good terms with all of them; when the inhabitants of the castle refer to "the Family", they generally mean Christopher's staff as well as his actual relatives.
The domestic staff include the housekeeper (Miss Bessemer), a butler (Mr Frazier), Cook (who is female), assorted footmen (one named Roberts), assorted maids (including Euphemia and Mary, who do the childrens' rooms and supervise them at meal times, and Nancy, who works in the kitchen), and a boot-boy. The grounds staff include various gardeners (we're not told whether the stables have been kept up since the advent of the motor car).
Christopher's study, the location of which is not specified, is large and sun-filled, with bookshelves all around the walls. There is a desk, but also a sofa and a leather armchair.
The old lady with the mittens works in one of the offices that opens onto the gallery at the top of the main staircase.
Michael Saunders' workshop is set up in the workroom that Christopher discovered as a boy. There is a pentagram painted on the floor, and a burning cresset hanging from the ceiling. There are numerous trestle tables - one covered in torts and limbecks, one piled with books and scrolls, one with signs chalked all over it. There are shelves all around the walls, with books and ingredients in big jars, including a big jar of dragon's blood (which Chrestomanci presumably has permission for). There is also what appears to be a small mummified dragon.
When there are no visitors, the Family dines early so that the children can have dinner with everyone else. Even then, dinners are always formal, with everyone in evening dress, gathering in the adjacent drawing room and all being let in at once, and footmen serving the food; the dinner gong, rung a half-hour before dinner and audible all over the castle, is one of the few sounds ever to break the castle's general air of stillness.
In fine weather, they sometimes have afternoon tea on the lawn.
Christopher has a strictly-enforced rule that nobody is allowed to talk shop at mealtimes, partly as a result of how difficult it was for him as a child, surrounded by people ignoring him and talking to each other about things he didn't understand.
The family live in a region spanning the place where the old part of the castle meets the new. The corridors have white walls with paintings hanging on them, and electric lights at intervals, and polished floors with soft green carpets running down them. Although connected to the working part of the castle, it has its own exterior door; the door, just on the new side of the divide, obscure and screened by a shrubbery of rhododendron trees.
The children have breakfast and lunch together in the playroom, which is two flights up from ground level in the newer part of the castle. When there are guests to dinner, they have dinner there as well. The playroom is a square, airy room with a row of big windows. It is a bit shabby: everything in it is battered, and sometimes also stained. There are cupboards full of toys. There is a little lift set into the wall near the fireplace, on which the food comes up from the kitchen.
The school room is adjacent to the playroom, and contains all the things a genuine school room should have: blackboard, globe, glass-fronted bookcase, authentic school-room smell. Lessons start at nine o'clock every day except Sunday and continue, with breaks for morning tea and lunch, until some time in the afternoon; on Wednesdays and Saturdays, there are no lessons after lunch. They also get their pocket money on Wednesdays, five shillings each.
Every Sunday, the Family attend the morning service at the church in the village.
Gwendolen's room is in the newer part of the castle, two flights up from ground level, and just along the corridor from the nursery. It is large, with a rich, soft Turkey carpet covering most of the floor, and blue velvet upholstery, with matching curtains and bedspread. The chairs and dressing-table have gold trim. The dressing-table has a long oval mirror surrounded by a gilded wreath. The wardrobe has painted garlands and maypole dancers on it. There is a bathroom en suite, with blue and white tiles and a sunken bath/shower, and blue towels and shower curtains. Cat's room is up a twisty staircase in one of the old towers (in a position corresponding to the workshop). It is round, and has three windows and a fireplace. The walls are whitewashed. There is a private bathroom down the passage, with a claw-foot bath and separate shower, with red towels and shower curtain.
A smooth lawn with cedar trees runs along the entire front of the newer part of the castle. Further out from that is a formal garden, with straight gravel paths running between box hedges, yew trees clipped into severe pyramids, and beds of yellow flowers. Beyond that is an apple orchard. Then a goldfish pond. Then a rose garden. Elsewhere in the grounds there are pine trees, oak trees, grape vines, and a wood of horse chestnut trees, where Julia and Robert have a tree-house.
Most of the furniture and suchlike in the castle is spelled to raise the alarm if it's removed.