Orsinium, also called Nova Orsinium, is an Orcish city province located within Tamriel. It featured prominently in the The Elder Scrolls II: Daggerfall as the Orcish capital city. While technically being under the sovereignty of the Empire, Orsinium has in the past not been readily accepted by the other provinces of Tamriel. However, in 3E 399, Emperor Uriel Septim VII sought to improve relationships between the Empire and Orsinium through diplomacy, increased trade, and confederacy. Orsinium is located inside the Breton province of High Rock, in the west of Tamriel and as such Orcs co-inhabit the region alongside Bretons.
Orsinium (Elvish: pariah town) was founded by Orc chieftain Torug gro-Igron, after Warlord Thulgeg led a great emigration of Orsimer and Goblins to the Wrothgarian Mountains. At first it was just a small collection of huts but as word spread to the other Orcs of Tamriel about this rising civilization high in the Wrothgarian Mountains it soon grew to house more permanent structures.
In its early stages, the other races of Tamriel deemed it a place ruled by savage law which raided its neighbors along the local river (the Bjoulsae River). It was thought by the Bretons to be little more than a desolate mountain region where Orcs scratched a meager living off rocks and secretly coveted the lands and the settled livelihood of their valley-bound neighbors. Orc historians however, claim this is simply Breton superstition and exaggeration. They claim Orsinium was always a peaceful land whose inhabitants made their way by simple agriculture and commerce.
With no province to call their own, the Orsimer became little more than pests and monsters in the view of the average Tamrielic citizen. Many Orcs attempted to set-up new Orsiniums but with no luck. They were always destroyed before they could be properly established.
- Main article: Orsinium (Online)
The Second Orsinium existed during the Second Era during the Three Banners War. Little is known about it, and it is unknown when it was founded. The city was under the control of Kurog gro-Orsinium during 2E 583, who united it with the Daggerfall Covenant. It is unknown when it was destroyed.
- Main article: Orsinium (Daggerfall)
An Orc visionary named Gortwog gro-Nagorm acquired the site of the former civilization of Orsinium and began reconstructing a new city for the Orsimer of Tamriel. As it grew, many believed it would succumb to the same fate as its predecessor. Gortwog though, proved to be a superb politician and diplomat and managed to make negotiations with Orsinium's neighbors which saw Orsinium prosper.
Orsinium has asked the Imperial authorities to raise it to Provincial status, making it recognized as a fully-fledged Province of Tamriel. Its request is currently under review. However, given the likelihood of a stable future with its previous rival High Rock, many believe Orsinium now has a very good chance of succeeding in its goal.
There is however, a religious conflict in Orsinium which shows signs of becoming a major problem. In accordance with tradition, the Orsimer have always worshipped the Daedra lord Malacath as their deity. Orsinium's current leader, Gortwog, however, has controversially claimed that Malacath is in fact a fake and has set up a priesthood dedicated to the worship of the ancient Orcish hero, Trinimac (this has caused controversy as Trinimac was said to have been devoured by Boethiah and afterwards became Malacath).
Gortwog's belief that Trinimac still lives and that Malacath is a mere demon is currently the official view taken by the majority of the leading priests in Orsinium. A handful of Orcs within Orsinium and the majority of Orcs outside of it view Gortwog's beliefs as heresy. Many of Gortwog's supporters grow fearful that turning their back on Malacath may prove to be a terrible mistake.
Some time in the early 4th Era Orsinium was once again sacked (The exact date or by whom it was sacked is unknown). Like before, it was rebuilt, but this time not in the Wrothgarian mountains like the two previous incarnations of the Orc kingdom. The new Orsinium was built in the Western Reach mountains in between Skyrim and Hammerfell. 
- The Elder Scrolls II: Daggerfall
- The Elder Scrolls V: Skyrim (Mentioned only)
- The Elder Scrolls Online (Mentioned only)