From the Wikipedia page on Teesside [1].

Teesside is the name given to the conurbation in the north east of England, United Kingdom made up of the towns of Middlesbrough, Stockton-on-Tees, Thornaby, Billingham and surrounding settlements near the River Tees. It was also the name of a local government district between 1968 and 1974—the County Borough of Teesside.

Teesside Archives collects and preserves archival material from churches, official and private sources.

The website is [2]