Teesside, or more properly the Metropolitan County of Teesside is one of six counties within the Kingdom of Northumbria. It borders only the county of Durham to its north and west, also bordering the United Kingdom to its south. With Newcastle it is one of two metropolitan counties in Northumbria.
Kingdom of Sorrenia
The Teesside area was first claimed by Northumbria's predecessor - the Kingdom of Sorrenia - during the 'Great Expansion', when the Sorrenian government greatly expanded the territorial claim of Sorrenia to encompass all of the North East, North Yorkshire and much of the North West. The new Teesside county was far larger than the contemporary one, including the towns of Stockton-on-Tees and Darlington, stretching north to include Durhamite towns like Hartlepool, and south to include areas of Yorkshire like Kirkby. This made Teesside one of the largest metropolitan counties in Sorrenia, and the fifth largest by area.
It was during this period that the 'Teesdale Question' first emerged, as many pushed for Teesside to also include the Teesdale region which was instead at the time included within the South Durham county.
Kingdom of Northumbria
The contemporary Teesside county was shrunk considerably to include only claimed land south of the River Tees. Important settlements like Darlington and Stockton-on-Tees were placed in a single enlarged Durham county - as is the case in the United Kingdom - but unlike in the UK, no devolved powers were granted to the area, which is instead administered by the Prince Bishop from the City of Durham.
Teesside is one of two metropolitan counties in Northumbria. It is dominated by the city of Middlesbrough located in the west of the county. A number of smaller coastal towns like Redcar are found in east Teesside.