The Riverlands

The Riverlands are a central and prosperous kingdom, ruled by the tullies. It is home to the Ruby ford, and the legendary fortress of Harrenhall. 
=== Terrain ===
The Riverlands is named after the many rivers it is home to. The biggest one of these is the Trident, which runs through the entirety of the Riverlands with its three forks. The control over these forks is crucial for control of the Riverlands, for it is a strategic position that can cut any alliance in the Seven Kingdoms in half. It's central placement on the continent of Westeros can be credited for this, as this is what happened during the Second Clash, when the Westerlands and the North couldn't consolidate their armies and were subjected by defeat in detail by Stannis II. The Riverlands are also filled with dense forests, which offer even more ways to defend the lands. It's central position also acts as a double-edged blade because when a River Lord/Lady should find themselves without allies they can be caught up quite literally at the center of all the violence. This can be seen during the time of the Trident Union, where surrounded on all sides, Joseph Dondarrion could not hold out for long until he was overrun by an assault from multiple kingdoms on many fronts.
=== Economy ===
The peacetime economy of the Riverlands is notable, because of the many trade hubs and fertile lands that it holds. Some small towns in the Riverlands, like Stony Sept and Maidenpool, are as well-traveled as great cities like White Harbor and Sunspear. This influx of trade, combined with the fertile earth, means that the peacetime economy of the Riverlands rivals that of the Vale, and even that of the Reach. They are second in grain production only to the reach, and second in gold production only to the Westerlands. This is usually erased as soon as war is declared, as the central place of the riverlands usually means their towns and lands are burned to the ground during great wars. This was true for the war of the five kings, and both the first and second clash.
=== The Origin of the Commonfolk ===
The long history of suffering and raiding the people of the Riverlands have had to endure means that commonfolk demagogues have had a long history of succes in the Riverlands, which were also made possible by the very lenient rule of King Bran the Broken. Preaching such things as complete equality and the abolishment of the noble ruling class, it was considered to be a substantial threat even in it's infancy. 
A few years before the death of King Bran the Riverlands Kingdom was reformed into the Trident Union by the Brotherhood without Banners, heroes of the common people during the War of the Five Kings and now the heralds of a new regime led by Joseph Dondarrion, who deposed the Great House of Tully but not before they were rescued and put in hiding by Beric Dondarrion II. After the Slaughter at Harrenhal where both the Crusader State of the Crownlands and the Trident Union destroyed most of if not all of eachother's forces, the Trident Union was forcefully dissolved by Lord Beric and House Tully was restored to their seat in Riverrun. This did not cause the idea of a kingdom ruled by the people to go away as it was remembered fondly by the Riverlander peasantry and smallfolk.