The North

"The North is by far the largest of the Seven Kingdoms; it can fit the other six inside it. Not that the others care... cold and damp, that's how the southerners see the North. But without the cold, a man can't appreciate the fire in his hearth. Without the rain, a man can't appreciate the roof over his head. Let the south have its sun, flowers and affectations. We northerners have home."

- Jon Snow

The North is part of the independent Kingdom of the North and was previously one of the constituent regions of the Seven Kingdoms. The North is ruled from the castle of Winterfell by House Stark. It is the largest of the nine major regions of the continent, almost equal in size to the other eight combined.

According to legend, the Kingdom of the North was established eight thousand years ago by Bran the Builder, the founder of House Stark, who constructed the Wall as a shield against the possible return of the White Walkers. The North is the only region where the First Men were able to resist the Andal Invasion, six thousand years before the War of the Five Kings. As a result the North is the only region of Westeros in which the ethnic makeup is predominantly First Men, and the only region where the culture, customs, and traditions of the First Men still predominate. Among these is the belief that the man who passes the sentence of death must swing the sword himself. In particular, the religion of the First Men, the worship of the Old Gods of the Forest, is still the dominant faith in the North. The Faith of the Seven introduced into southern Westeros by the Andals has found little foothold in the North. As a result, warriors from the North are not "knights", because "knighthood" is a code of values associated with the Faith of the Seven. However, mounted warriors are still an honored and esteemed military asset in the North, so that while northmen like Ned Stark may not carry the title "Ser", Northern cavalry are functionally equivalent to mounted knights.

Bastards born in the North are given the surname Snow. People of the North are known as Northmen (or Northerners), and, derogatorily as wolves, in reference to the sigil of House Stark.

Geography
The borders of the North are held to be the sea to the west and east, the Wall to the north and the hills and bogs of the Neck to the south. Greywater Watch and its ruling house, House Reed, are the southern-most noble family owing fealty to Winterfell.

The climate of the North, though harsh overall, varies from cool (maritime) temperate around the Neck, to cold temperate around Winterfell, and to subarctic at the Wall. The lands south of Winterfell leading to the Neck are almost as fertile as the Riverlands to the south, and are the most agriculturally productive region of the North. The Neck itself is filled with swamps. Snowfall generally increases as one moves north along the Kingsroad.

Castles

 * House-Stark-Main-Shield.PNG Winterfell, the seat of House Stark, capital of the North.
 * House-Mormont-Main-Shield.PNG Bear Island, the seat of House Mormont.
 * House-Cerwyn-Main-Shield.PNG Castle Cerwyn, the seat of House Cerwyn.
 * House-Glover-Main-Shield.PNG Deepwood Motte, the seat of House Glover, recently liberated from Ironborn occupation.
 * House-Bolton-Main-Shield.PNG The Dreadfort, the ancient seat of House Bolton (now extinct).
 * House-Reed-Main-Shield.PNG Greywater Watch, the seat of House Reed, the southernmost house sworn to Winterfell.
 * House-Hornwood-Main-Shield.PNG The Hornwood, the seat of House Hornwood.
 * House-Karstark-Main-Shield.PNG Karhold, the seat of House Karstark.
 * House-Umber-Main-Shield.PNG Last Hearth, the seat of House Umber.
 * Torrhen's Square, the seat of House Tallhart.
 * House-Manderly-Main-Shield.PNG White Harbor, the seat of House Manderly, the principal city and port of the North.
 * Flint's Finger
 * Moat Cailin, a ruined castle at the northern edge of the Neck, currently unoccupied.
 * Barrowton, a holdfast in the Barrowlands, seat of House Dustin.
 * Oldcastle
 * Ramsgate, a holdfast at the mouth of Broken Branch.
 * Widow's Watch, the seat of House Flint, vassals of House Stark.
 * House-Forrester-Main-Shield.PNG Ironrath, the seat of House Forrester, vassals of House Glover.
 * House-Whitehill-Main-Shield.PNG Highpoint, the seat of House Whitehill, vassals of House Bolton.
 * House-Glenmore-Shield.PNG Rillwater Crossing, the seat of House Glenmore, vassals of House Ryswell.

Regions

 * The Neck
 * The Rills, ruled by House Ryswell.
 * Cape Kraken
 * The Barrowlands
 * Stony Shore
 * Sea Dragon Point
 * Wolfswood
 * The Grey Cliffs

Islands

 * Bear Island
 * Skagos
 * Skane

Coastal Areas

 * Bay of Ice
 * Bay of Seals
 * Blazewater Bay
 * The Bite

Rivers and lakes

 * White Knife
 * Broken Branch
 * Weeping Water
 * The Last River
 * Long Lake

In the books
In the A Song of Ice and Fire novels, the North is an area vast in size but relatively light in population. The North, due to its location, is particularly badly affected during the long winters, with thousands of people killed and famine not an uncommon occurrence due to the inability to raise crops for years on end, outside of special greenhouses and castles built on or near hot springs, like Winterfell, or volcanic vents, like the Dreadfort of House Bolton.

The people of the North, popularly called "northmen" or "notherners", are known as a hardy, tough breed who hold the comforts of the warm, "soft" south in disdain. They worship the old gods of the forest, and the "new gods" of the Andals have made little headway in the North. With a few exceptions, the warriors of the North refuse to take holy orders and thus cannot become knights.

Some of the northmen live in remote, distant areas where they act little more as clans and tribes of savage warriors. Even these remote folk are vassals of the Starks, however, and are allowed to maintain their own ways and traditions as long as they remain loyal to Winterfell - which most of them usually do, as the Starks have a history of being just and honorable rulers. The Starks treated the mountain clans with respect by referring to them as if they were small-scale noble Houses, i.e. calling them "House Wull" and "House Norrey", instead of dismissively thinking of them as lowly "clans".

Characters in the novels frequently remark that the North is almost as large as the rest of the Seven Kingdoms put together (a remark repeated in the TV series). In the World of Ice and Fire sourcebook (2014), the in-universe author Maester Yandel explains that while this is a very common saying, maesters have conducted fairly accurate land surveys over the centuries, which have revealed that the North is actually closer to about one third of the total land area of the Seven Kingdoms, not one half.