Recorded in many forms including Tanwall, Tanswall, Tanswell, Tanswill, Tentwall, Tentwell, Tinwell, Tennewell, and Tynewell, this is an English locational surname. It originates either from an existing place such as Tyne Mill in County Durham or Tynewydd in Glamorgan, South Wales, there does not seem to be any place with the spellings of any of the known surname forms, or perhaps more likely from a now 'lost' medieval hamlet, which was probably associated with the River Tyne in Northumberland. An estimated five thousand surnames originate from 'lost' medieval villages, of which the only public reminder in the 20th century, is the surviving surname often, as with this one, in a variety of spellings. The name translates as 'the spring on the Tyne' from the pre 7th century Olde English 'tyn' meaning river, and 'waella' a spring, or possibly in this case a branch or tributary. Locational surnames are 'from' names. That is to say names given to people after they left their original homestead, and moved elsewhere. The further they moved, the more likely it is that the spelling was corrupted. In this case early examples of the recordings include: John Tynewell, who married Katherine Birth, at St Margarets church, Westminster, on February 28th 1633, Dorothy Tinwell, who marrried Robert Binkes at the church of St Bartholmew the Less, in the city of London, on February 7th 1664, Francis Tennewell, who married Mary Bartlett at the famous church of St Mary-le-Bone, also city of London, on January 20th 1796, and John Tanswell, at St Lukes Chelsea, westminster, on July 6th 1800.