In many places - particularly in places where Western culture is dominant - the Hedge lives up to its name, appearing as a thick hedge of thorny brambles, but it may take many forms. However it appears, be it swamp or desert or jungle, the Hedge is always wild and seldom safe; its thorns tear at the mind and soul as well as the body, leaving a Changeling's memories and often identity in tatters.
Within the Hedge are paths called trods which lead from gateways to other significant locations. Many trods run close to the mortal realm, which is visible when it is near. Others lead deeper into the Hedge, to Hollows - stable areas claimed or cultivated by Changelings or other fae creatures - or to Arcadia, the realm of the Fae. It is impossible, however, for any but the True Fae themselves to enter Arcadia from the Hedge; while mortals can blunder into the Hedge on their own, they only enter Arcadia when taken by the Fae.
The Hedge is full of life; as well as the thorns there are many plants, including mystical Goblin Fruits of many kinds. There are also creatures of all shapes and sizes, which the fae refer to as Hobgoblins. Whether these creatures are native to the Hedge, or are creatures originally from Earth (or possibly even Arcadia) who have been warped by prolonged exposure, is debated by the fae, though many agree that these explanations aren't mutually exclusive. Most Hobgoblins are hostile, though a rare few are relatively benign and may be befriended by Changelings.
Changelings may enter the Hedge through gateways which exist in any number of places, and may even create their own through the power of Glamour. Any portal - be it a door, window, or merely a gap in a fence or mundane hedge - can be a gateway. Some gateways have existed for centuries; some older gateways may even be opened, accidentally or otherwise, by mortals. These most commonly require a key, a specific combination of objects, circumstances and/or actions that must come together to open the gateway. Changelings do not need a key.