Seven Kingdoms

The Seven Kingdoms of Westeros, sometimes simply known as the realm or the Crown, was the dominant government of the continent of Westeros consisting of the North, the Riverlands, the Iron Islands, the Westerlands, the Stormlands, the Reach, The Vale, and Dorne. It was a  ruled over by a single sovereign for life. The royal family was House Targaryen, a noble house from Valyria who conquered all of Westeros during Aegon's Conquest. The ruler of the Seven Kingdoms, known as the Lord of the Seven Kingdoms, sat the Iron Throne, which became synonymous with the kingdoms themselves.

The Seven Kingdoms stood virtually unchallenged in its dominion over Westeros. In its early years, Dorne resisted the rule of House Targaryen, and its dominion did not extend to the lands beyond the Wall; but the rest of the continent bent the knee and remained subservient to the Crown.

Geography
The Seven Kingdoms extended from the Wall to the southern tip of the continent of Westeros at Dorne, as well as the nearby islands. It was located west of Essos and north of the Summer Isles. To control the kingdoms he conquered, established regional lordships, that were directly subservient to the King of the Andals, the Rhoynar, and the First Men, who would oversee their constituent regions. For example, the Lord Paramount of the Trident, a title held by House Tully, oversaw the Riverlands.

House Targaryen also carved out a new region, the Crownlands, which the directly ruled over. This region consisted of the fertile lands that sat alongside the Blackwater Rush, south of the Vale, east of the Westerlands and the Riverlands, and north of the Stormlands.

The region of Dorne was contested. Though the Seven Kingdoms claimed dominion over Dorne, Aegon's Conquest failed to bring them into the fold. This led to a series of successive wars that sought to bring Dorne into the fold and make the name of the Seven Kingdoms legitimate.

Several roads connected the Seven Kingdom to one another. The most major of these roads was the kingsroad, which ran two thousand miles from the Wall to King's Landing, the capital. The roseroad connected the Reach and Oldtown to King's Landing. The goldroad connected the Westerlands to King's Landing. There was no road leading from King's Landing to Dorne, or vice versa, forcing the Dornish to pass through the Reach, with the permission of House Tyrell, and then use the roseroad to travel to the capital.