House Harroway of Harrenhal was an extinct noble house of the riverlands, sworn to House Tully of Riverrun. Their seat was the great ruin of Harrenhal on the northern shore of the Gods Eye, the largest castle in all the Seven Kingdoms, though the Harroway lords were the third family to hold it and not the last to be broken by it. Lord Harroway's Town, a modest settlement in the riverlands, takes its name from a former lord of the line, suggesting the family held lands and prominence in the region long before the Targaryen Conquest.
The house rose to its greatest height under Lord Lucas Harroway, who received the lordship of Harrenhal in 37 AC after the extinction of House Qoherys. His daughter Alys became the second wife of Prince Maegor Targaryen in a Valyrian ceremony on Dragonstone in 39 AC, a match denounced by the Faith as sinful fornication, and in 43 AC Maegor named Lord Lucas his Hand of the King. The height of Harroway power was brief. When Queen Alys gave birth to a monstrous stillborn child, Maegor's third wife Tyanna of the Tower whispered that the babe was not the king's. In 44 AC Maegor ordered the deaths of every Harroway he could find, in King's Landing, at Harrenhal, and in Lord Harroway's Town alike. Alys was executed alongside her father and the women of her household. Only later, in 48 AC, did Tyanna confess on her own deathbed that she had poisoned the child in the womb. House Harroway was no more.