The Hedge is the thorny barrier that lies between the mundane mortal world and the Thousand Kingdoms of Dread Arcadia. This space is very important to Changelings, providing them access to magic and other abilities that mundane mortals can not.
In the city of London, the Hedge almost invariably appears as immaculately landscaped Victorian hedgerows, complete with softly glowing gas lights and the general sense that the ground beneath your feat is paved in cobblestone. The farther away you get from the city center, the less predictable the Hedge becomes, transforming from Victorian streets to overgrown rot and finally dense impenetrable forrest filled with all manner of horrible things.
The Empire credits the order of the Hedge in the center of London to the stabilizing presence of The Empress and the Empire in general, while the untamed areas are generally assumed to fall under the purview of the less-trustworthy Outerfreeholds. While some argue that this order is, in fact, unnatural, (as most clean and clear Trods actually are controlled by The Gentry and thus are very dangerous) the benefits are obvious as the Trods to and from locations in the heart of the city are considered the safest of there kind on earth.
Beyond the overgrown forests in the Hedge lies the Thorns and Brambles - the physical barriers between the Hedge and Dread Arcadia. The Thorns rend and rake anything that comes through them, scouring the mind and the soul of any individual who passes through. Dr. Steven Chandler has asserted that it is this process has made the Changeling community "soulless" and thus incapable of "true magic".
Chunks of memory and soul can be retrieved from the Brambles and are done so by Mr. Shaitana and his associates as well as Queen Mary and the Conclave of the Wyrd. These chunks are highly prized as they can be "used" by even mortals to gain memories and flashses of feeling from the Changelings that lost them. They are also apparently quite addictive, with Shaitana structuring an entire business out of their sale.
Entrances and Exits
The Hedge is notably easy to access in central London but is much more difficult to access from the outskirts of the city. Doorways into the Hedge have been opened across the world, and once opened, they may fall dormant but never truly close. These locations are referred to as Rabbit Holes by the Empire. If a Rabbit Hole becomes incapable of fully closing it is typically refered to as a Scar or Wound. The most notable Scars in the Empire are the locations of the Jack the Ripper murders.
It was discovered early on in Imperial study that there was a portion of the Hedge that you could enter only by accessing specific entrances above the ground level. Mr. Black's Rules specifically forbid entering the Upper Hedge, as it is seen as being incredibly dangerous. The body of David Picket-Frost was disposed of in the Upper Hedge.
The Deep Hedge is likewise feared by most Imperial citizens - it is the deepest darkest portion of the Hedge accessible only from underground. Creatures such as the Nihil are rumored to dwell in the Deep Hedge. The freehold known as The City of Underlondon exists in this Deep Hedge, but few know how. Mr. Black's Rules also forbid entering this area, for fear of personal safety.
The Hedge contains various degrees of Fog at any given point, always obscuring the ground of the Hedge and the ankles of anyone standing in it. A key sign that an entrance to the Hedge is active at any point is a high degree of Fog pouring out of an unlikely area. The deepest portions of the Hedge contain so much Fog that people can barely see three inches in front of their face.
All Trods Lead to London
One of the unique features of the London Hedge is that all trods in the Empire, from Bristol to Bangkok, have a chance of leading out into London. This fact alone has contributed to the diversity and sheer number of freeholds in the city, as stolen Changelings from all over the planet are deposited back in London proper. This also means that keepers and bizarre and unnatural Hedge-Beasts from around the globe find themselves drawn into the city to plague the Empire.
The confluence of Trods and pathways has led to the existence of The Axis Mundi a mystical passageway that opens "secret" trods through the Hedge to various cities in the Empire across the globe.
Technology doesn't operate as wanted in the Hedge and the more complex the tech the less it seems to work. Many foolish younger Changelings have seriously injured themselves attempting to use smartphones in the hedge only to have them Explode. All complex machines break down almost instantly in the Hedge and those that do not often warp in ways their users never expected (or wanted). Steam power and many Victorian-era devices and developments seem to work with a degree of reliability but even they carry risk.
It goes without saying nearly all forms of firearms are totally useless in the Hedge. Automatic and semi-automatic weapons go horribly wrong when used and even single shot modern guns can be problematic.
The only forms of firearms that have any kind of reliability in the Hedge are muskets and flintlock pistols (and they have the natural disadvantages of older technology). Because of this, most Changelings use blades as weaponry in the Hedge (if required) and simple bows.