Ruathym refers to both the region and to its component islands.
The island itself is rugged and barren, roughly 110 miles (185 km) long and 50 mi (80 km) at its widest, lying NNW of the Moonshaes and NE of Amia. The northern tip lies almost due west of Daggerford and the southern tip almost due east of Amia's Kohlingen. It consists of a central mountainous spine, oriented roughly north-south, around which is a sparsely-inhabited coast of consisting mainly of cliffs on the western side, broken here and there by fjords. It is an island of rocky, rugged coasts, high cliffs, and is stormswept nearly eight months of the year. The farther north you go, the wetter it gets, and the higher you go, the colder it gets. The northern tip is almost perpetually in the grip of either thunderstorms or thick fog. The land is slightly more hospitable on the eastern coast, and the south-eastern portion of the island is particularly fertile, relatively speaking, composed of rolling hills with occasional rocky outcrops. It has many grassy hillsides and a few forests. Scattered steadings and villages cluster around the isle's fjords and inlets. Its economy is based primarily on raiding, farming, mining, and shipbuilding.
The main island of Ruathym itself consist of four Jarldoms. The largest is Ottar, in the south-east, site of the de facto capital of Holgerstead, a small city of about 5000 and home of the ruler, known as the First Axe. Ostland, in the north-east, is the second largest; its main port is the town of Osthavn, with a population of roughly 2000. Both are fairly popular ports of call for ships travelling the Trackless Sea between Amia, the Moonshaes and the Sword Coast. Travel on the roads in Ostland is generally safe, if somewhat lonely; they are patrolled by local forces, the Jarl's Everwatch Knights, or contingents of War Knights from their dwarven-built fortress of Rethgaard on the eastern coast of Ostland. The two other Jarldoms are little more than small towns clustered around their Jarl's hall at the end of fjords on the storm-lashed eastern coast. The Jarldoms of Ruathym are regular combatants with the coastal city of Luskan, a rivalry that goes back over a thousand years. More recently, the two have been engaged in an on-again, off-again war which began as a result of an alleged act of piracty by a Ruathymi ship against a Luskan merhant vessel. Tensions are still high and their ships often take potshots at each other as they pass. The First Axe consolidated the four petty jarldoms on the island into a single unified nation during the war. At this time, however, the jarldoms of Ruathym and the minor island jarldoms of Wiltun, Caraigh, Axard and Nerth owe allegiance to the First Axe in little more than name only.
Ruathym is the ancestral home of the Northlanders, the barbarians who colonized the northern Moonsaes and Luskan. Originally from the Moonshaes, the Northmen migrated northwards to Ruathym and then eastwards to the norther Sword Coast (rather than westward toward the island of Amia, which at that time was home mainly to Mylocks and a few dragons), settling in the area of Luskan and Neverwinter in the few hundred years prior to the start of Dale Reckoning. The island is perhaps best known as being the one-time home of Uthgar, the deity of the Uthgardt barbarians. Both Labelas Enoreth and Clangeddin Silverbeard are also said to have appeared there during the Time of Troubles.