Old Woods

The Old Wood (aka the Wood and Olds Woods) are old forest lands that borders the Kingdom of Daventry to east about four miles away from the castle. The forest is vast stretching many miles to the north and south. It is a kingdom of Fairie ruled by Quilli'ehennan, and Culatha the king and queens of the Wood, thus the forest is a neighboring kingdom to Daventry. The Old Woods where faeries live are also known as faery woods. The forest has existed since before the fairies moved there, and has existed there long before there was even a Kingdom of Daventry. The wood is indeed Old, and has existed in times before humans, and before faeries even.

Background
The Old Woods were not merely old in name, but had been there longer than there had been a kingdom of Daventry. The Old Woods contain faery magic, and magic older than the faery.

King Graham and Valanice were the first to enter the forest after being summoned by the Elkrider, in order to talk to the Fairy King Quilli'ehennan, and find out that Graham had to save Ahi'aorina (who later became known as Culatha) from the imps of Sorrowing Court.

Years later Rosella entered the forest to get away from some sloks, and was nearly killed by some mischievous fairies, but was saved by a white faery (who claimed she was a friend of her father). Who then lead her out of the forest.

Years later Alexander passed through the forest on his way to dark castle. He encountered the fairies, and Culatha gave him Green Wallet to help him on his journey because the floating castle not only threatened Daventry but the Old Woods as well.

Time appears to move differently in the woods than the surrounding lands, as people going into the old woods may only be there a few minutes from their POV, but hours or days or even years could have passed outside the forest. What may seem like an hour, could be a year or more. Though the effects aren't always the same, and may be different each time they enter the woods, it is caused by the effects of faery magic, and magic much older than even the fairies.

The Cyclopedia had this to say about Old Woods, and Faery woods in general;

"Old Woods; Any of several stands of old-growth deciduous forest, generally inhabited by woodland fairies."

"Faery wood; Faery woods exist in several kingdoms of the eastern continent."

Behind the scenes
The Wood is called the Old Wood in Kingdom of Sorrow and The Floating Castle, and the Old Woods in See No Weevil.

In The Floating Castle, Alexander travels east, towards a river into the eastern edge of the Old Wood, and then north a little ways before coming out into Daventry's northern farmlands.

In Kingdom of Sorrow the Graham travels through the Old Wood to the east, to the lands beyond. He later passes along the southern edge of the woods, and then travels north to get to Daventry.

In See No Weevil Rosella travels a bit south and east into into the Old Woods, she comes out later they come out to the side of the north-south road. Its also explained that Old Woods is a number of groves. There may be implication that the Woods extend parallel to the souther border of daventry to the east and west. In which case the book showing another grove than the one seen in previous novels, which might explain the use of the plural in cyclopedia entry.

It's unclear if the three sections of the Old Woods from the three novels are connected or separate groves. Although the Fairie live in all three, and Culatha rules at least two locations if not all three.