Winterfell is the seat of House Bolton (formerly House Stark). It is a very large castle located at the center of the North, from where the head of House Stark rules over his people. A small Godswood is enclosed within the walls. It is the capital of the North under King Robb Stark. The castle is located alongside the Kingsroad as it makes its way from the Wall to the capital at King's Landing, more than a thousand miles to the south. It is situated atop hot springs which keep the castle warm even in the worst winters. Winding tombs below the castle contain the remains of Stark kings and lords and record the history of the ancient family. The castle has stood for millennia.
The castle is put to the torch by Ramsay Snow after Theon Greyjoy was betrayed by his own crew. This burned out the wood portions of the castle, though the core stone structures remained fundamentally intact, as did the enclosed godswood. After the fall of Moat Cailin, the Bolton army relocated to the ruined castle in order to restore it as the seat of the rulers of the North.
According to legend, House Stark has held a castle at Winterfell for 8,000 years, though it has been considerably expanded over the centuries.
Eddard Stark rode south to fight in Robert's Rebellion after his father and older brother were killed by the Mad King. At the end of the war, he returned to Winterfell with his new wife Catelyn Tully, their infant son Robb Stark, and also Eddard's bastard son Jon Snow whom he had fathered during the war. After the Greyjoy Rebellion eight years later, Eddard took Theon Greyjoy back to Winterfell as his ward - partly as a political hostage, but perhaps partially to raise him to be an honorable man
After the death of Hand of the King Jon Arryn, King Robert Baratheon makes a formal visit to Winterfell along with much of the royal court, including his wife Queen Cersei Lannister, their three children Joffrey, Myrcella, and Tommen, as well as Cersei's brother and Kingsguard member Jaime Lannister, and their brother Tyrion Lannister. A great feast is held in Robert's honor. Robert visits the tomb of Lyanna Stark and asks Lord Eddard to return with him to King's Landing as his new Hand, and to solidify the union between their two Houses by betrothing Eddard's elder daughter Sansa Stark to Crown Prince Joffrey.
Before they leave, however, while climbing a tower Bran Stark accidentally stumbles upon Queen Cersei having sex with her own twin brother Jaime, who then pushes Bran out of the tower window.
Bran survives the fall from the tower, though his legs are left crippled. Lord Eddard reluctantly departs down the Kingsroad with the royal party, along with Sansa and his younger daughter Arya Stark. Jon Snow also leaves Winterfell to join the Night's Watch at the Wall, accompanied by Tyrion. A Catspaw assassin sent by one of the Lannisters tries to kill Bran while he is still in a coma, but he is fought off by Catelyn and killed by Bran's direwolf Summer. Catelyn decides that Eddard must be warned so she leaves for King's Landing along with Ser Rodrik Cassel, leaving her eldest son Robb Stark in charge of Winterfell. After visiting the Wall, Tyrion stops at Winterfell on his return journey to the south, along with the Night's Watch recruiter Yoren. He gives Robb instructions for a special saddle which will allow Bran to ride without the use of his legs.
After word reaches Robb that his father has been arrested in King's Landing, he calls the armies of all the Northern bannermen. Robb departs Winterfell to lead his army to war in the south, and leaves Bran in charge as acting lord of Winterfell. His youngest brother Rickon Stark has a prophetic dream that Robb and his men will never return to Winterfell.
After Eddard is executed by Joffrey and Robb wins the Battle of the Whispering Wood, his bannermen hail him as the new King in the North. The North and the Riverlands declare themselves an independent kingdom under Robb. Winterfell is the de jure capital, though Robb remains with his armies fighting in the south. Now-Prince Bran Stark continues to rule as acting lord of Winterfell, with the guidance of Maester Luwin.
House Greyjoy - insulted at the prospect of allying with the Starks against the Lannisters - then counter-intuitively chooses to both declare the independence of the Iron Islands from the Lannister-controlled Iron Throne, and to attack the North while most of its armies are in the south. To impress his father Balon Greyjoy, the conflicted Theon leads a daring assault that captures Winterfell with under 30 men. Theon's ironborn were few, but the castle only had a skeleton defensive garrison left, and Theon used his intimate knowledge of the castle to lead his men over the walls using climbing spikes. Bran surrenders the castle to Theon. Maester Luwin barely manages to get a messenger-raven out warning of what has happened, after which Theon kills all the ravens to stop any further messages from getting out.
Theon, however, has no way of easily holding Winterfell so far away from the sea, even with most of the North's armies away in the south. Bran and his brother Rickon escape Winterfell along with Hodor and Osha, making his position tenuous, so he passes off the burned bodies of two orphan boys so he won't look weak - though instead this angers the rest of the North. When word reaches Robb's army camp in the south, his commander Roose Bolton says that he can send a reserve garrison led by his bastard son Ramsay Snow to besiege Theon. Robb decides to offer the ironborn at Winterfell safe passage back to the Iron Islands - if they will hand over Theon, so he can be executed as a traitor to the Starks. Theon's sister Yara Greyjoy briefly stops in Winterfell but only to warn him that they have no way of reinforcing or holding the castle, and he must withdraw while he can. Theon, however, fears that he has come to far too turn back now in failure.
Maester Luwin pleads with Theon that this is now who he is, and he must surrender and join the Night's Watch while he still can. Theon admits the truth in this but says he has come too far. In a rousing speech to his men, Theon accepts that he will die, but they will all die bravely fighting sword in hand, so the other ironborn will remember their example. Instead, one of his men knocks him unconscious from behind, to hand him over as part of the deal for their lives. Bran and Rickon - who had actually doubled back to hide in Winterfell's crypts - emerge after the Sack of Winterfell to find that it has been put to the torch. All of the wooden parts of the castle are burned out, though the core stone structures remain intact. Bran and his companions flee north to the Wall.
When word reaches Robb Stark at Harrenhal of the sack of Winterfell, the report sent by Roose's son Ramsay says that the ironborn put the castle to the torch before fleeing, put the inhabitants to the sword, and killed Bran and Rickon. The loss of Winterfell makes Robb look weak, particularly after the Lannisters secured victory in the southern front of the war against the Baratheons at the Battle of the Blackwater. Rickard Karstark loses all faith in Robb and calls him "The King Who Lost the North".
Not long afterwards, Boltons and Freys betray the Starks at the Red Wedding, destroying the Northern army, and resulting in the deaths of Robb and Catelyn. Roose Bolton personally kills Robb by driving a dagger into his heart. Subsequently, Walder Frey and Roose muse on their future plans, and Walder asks if as the new ruler of the North, Roose will relocate to Winterfell. He says that he will in time, after it is rebuilt. Walder also asks what really happened at Winterfell, because after Theon took the castle no further news came out. Roose explains that he indeed sent his bastard son Ramsay Snow to besiege Winterfell with the Dreadfort's remaining garrison, and Theon's men betrayed him, handing him over to Ramsay in return for promise of safe passage. Ramsay, however, "has his own way of doing things" - he flayed all of the ironborn alive, even though they surrendered in good faith, and spent the next year slowly flaying and horrifically torturing Theon. As for Winterfell, it was Ramsay and his Bolton army who burned the castle, and who massacred all of the inhabitants - the Boltons simply lied to Robb Stark about what really happened, as they were planning to betray him for months before the Red Wedding occurred.
After Ramsay manages to retake the fortress Moat Cailin from the ironborn, the path is cleared for the main Bolton army to return to the North, and enforce Bolton/Lannister rule. Roose, Ramsay, and Reek (the tortured, broken wreck once known as Theon) lead the Bolton army back to Winterfell.
The Boltons settle in at Winterfell, and bring in work crews and timber to start rebuilding the burned-out parts of the castle. The rest of the Bolton household has arrived as well, including Roose's new wife Fat Walda Frey. Following the death of Tywin Lannister, however, their already difficult hold over the North is even more tenuous: the armies of the Northern lords may have been destroyed, but the Lannisters left it to Bolton's army to rein them in, and will send no reinforcements so far out of the way. With Tywin dead, the Lannisters themselves are in a weakened position, and cannot aid the Boltons. Worse, Stannis Baratheon took his small remaining forces to the Wall, where they won a rousing victory in the Battle of Castle Black. Afterwards, Stannis intends to raise the North against the Boltons as a new sprinboard against Lannister rule. Stannis eventually leaves Castle Black to march to Winterfell, and begins to be supported by Northern houses who do not support the Boltons.
As part of a political plot, Petyr "Littlefinger" Baelish arrives at Winterfell from the Vale - bringing none other than Sansa Stark, to make a marriage-alliance between her and Ramsay Bolton. Littlefinger, however, informs Sansa that he truly plans for her to undermine the Boltons from within, hopefully to aid Stannis's probable victory, and if Stannis dies, to at least still be in a position to subvert the Boltons in the future.
With Stannis's army drawing closer to the castle, Roose Bolton intends to muster his strength within the walls of Winterfell with his legitimized son Ramsay. Meanwhile, with support from Queen Regent Cersei Lannister, Lord Petyr Baelish has raised an army of knights from the Vale supported by his own levies to march North and combat both House Bolton and Stannis, focusing on whoever wins the coming battle. In response to this predicament, Ramsay convinces his dad to lend him twenty "good men."
Ramsay and his twenty riders launch a sneak attack on the Baratheon camp and succeed in burning much of their food supplies, siege weapons, and horses. While Stannis does indeed reach Winterfell, his resources have been severely depleted and hundreds of his men have deserted due to snowstorms and Stannis's rash decision to sacrifice his own daughter Shireen to the Lord of Light. The army of House Bolton greets Stannis in open battle and after a short clash, smashes his army, and Stannis himself perishes soon after. However, with Winterfell in chaos, Sansa manages to escape the castle with help from Theon Greyjoy, putting House Bolton's future claim to the North in jeopardy.
Winterfell remains the Bolton seat of power. Following Sansa and Theon's escape, Ramsay attends to the corpse of his former bedfellow Myranda. Despite his affection for her, he orders Maester Wolkan to feed her body to the dogs. Later, Roose and Ramsay meet to discuss Sansa's escape, which has imperiled House Bolton's position among the northern houses. Roose stresses that they need Sansa in order to rally the northern houses against the Lannisters. Fearful of losing his inheritance to Walda's offspring, Ramsay sends his best hunters to recapture Sansa and Theon.
Later, Roose and Ramsay meet with Harald Karstark to discuss their predicament with Sansa. Ramsay's men had been found dead and he advocated storming Castle Black. Roose chastises his son's rash proposal as tantamount to turning the North against them. He also warns Ramsay that he would be discarded if he does not act more sensibly. After learning that Walda has given birth to a baby boy, Ramsay realizes that his position is shaky and murders his father. He then unleashes his dogs on Walda and his baby brother. Ramsay covers up his father's death by claiming that Roose had been poisoned by their enemies.
Smalljon Umber travels to Winterfell to forge an alliance with Ramsay, the new Lord of Winterfell and Warden of the North. In return for forging a military alliance between House Umber and House Bolton, Smalljon presents Rickon Stark, Osha, and the head of Rickon's direwolf Shaggydog. Ramsay accepts Smalljon's offer and takes Rickon captive. Later, Ramsay kills Osha after baiting her into killing him by leaving his fruit knife unattended. Ramsay then issues a letter to Jon Snow telling him that he has Rickon in his dungeons and demanding the return of his wife Sansa. In response, Jon and Sansa declare war on Ramsay and vow to retake Winterfell with the help of Tormund's Free Folk and several northern houses.
As the Second Battle of Winterfell turns in favor of the Starks, Ramsay returns to the castle and has the gate closed and barred. The giant, Wun Wun, breaks it down and Jon Snow enters the courtyard to face off with Ramsay. Jon prevails and refrains from killing Ramsay, who is taken to the kennels. Sansa later visits Ramsay there and, after speaking, watches as his starving hounds begin to devour their master. The Bolton banners are dropped from the ramparts and the Stark banners are once again hung in Winterfell.
Winterfell was the seat of the Stark family for generations until one-time Stark ward Theon Greyjoy seized the castle for his father during the War of Five Kings, Roose Bolton's bastard son, Ramsay, took it back but left it in ruins. Tywin Lannister awarded Winterfell to the Boltons after the Red Wedding for their service to the Crown. It remained in their hands until Jon Snow and Sansa Stark triumphed in the Battle of the Bastards. With Winterfell once again under Stark control, the Northern houses have pledged themselves to Jon Snow.