Ontario Fylk forms an exclave of Álengiamark to the northwest of the main country. It lies along the southern shore of Ontario Vatn with a border with Vinland along its western edge where the Breidurass is effectively blocked by the impressive Godifoss falls. To the south is Erie and to the east is Six Nations. It has often been regarded the 'backward' and neglected fylk of Álengiamark, its rural population often the butt of the more 'cultured' Atlantic coasts' jokes. The population the fylk is 810,300, the smallest of the seven Fylke and its capital is Ongaahrborg.
Ontario became a Álengsk subject during the 1210s when the Wenro tribe of the area, tired of constant raids and domination by their neighbours agreed to become a protectorate. This was the culmination of Queen Eydis's attempt to match Vinland's expansion into the Fraeburt Votnum. The Wenro's chief became an earl and the yearly campaigning of the Álengsk lords regularly included a spell in Ontario before moving to the west to campaign against the Eriac and Aniyunwiyans. However the Wenro were utterly dependent on Álengsk military might and when this failed in 1226 the region was swiftly overrun and divided between the Eriac and Seneca.
Ontario returned to Álengsk rule as more and territory was handed to Atamaja and her lords during the period of Aniyunwiyan dominance and stayed more or less loyal during the Great Unami Revolt. The Congress of Fjallasay in which divided the rebellious areas into new countries briefly considered giving Ontario independence but the lords, mostly Christian Aniyunwiyans repeated their allegiance to the Álengsk crown. It would therefore remain Álengsk even though it would be physically divided from the rest of the country.
Thanks to this separation there would be little internal migration. Instead, most new settlers came from Vinland looking for new areas to farm. And while it held back from what remained of the Althing in St. Hafdiss, a strong local government arose. Like other Álengsk areas it still splintered into smaller statelets but these maintained better relations with each other than elsewhere in Álengiamark. Therefore when Álengiamark was recentralised during the reign of Herridr I its parts accepted federation quicker than elsewhere. It officially became a Fylk in October 1735.
Its economy has long depended on cereal crops and flour milling and its fast flowing rivers were perfect for powering water mills, not only for flour but for running looms as the Industrial Revolution took hold. However its physical separation from the rest of Álengiamark meant it was reliant more on the Vinlandic economy, especially on Fjallasay downstream on the Breidurass, rather than the growing Álengsk towns and cities. The completion of the Erie canal in 1911 lessened this and allowed a much needed boost to its economy. Part of the Breidurass has been diverted for hydro-electric projects which power the entire Fylk.