Came across this:
This very unusual surname is of Olde English pre 7th century origins. It derives from twin hamlets in the far north of Yorkshire near Yarm, now known as High and Low Worsall. These places were first recorded in the famous Domesday Book of the year 1086 as \’Wercesel\’, the translation being \’Weorcs Hall\’. \’Weorc\’ was a personal name which occurred as the prefix of several northern sites, suggesting that it may have been tribal. The spelling changed to \’Wirkeshall in the year 1255, during the reign of Henry 11, the modern spelling being 16th century. Locational surnames were usually given to people who moved to other places, as an easy identification. As people only moved when they were forced to by economic circumstances, the spelling was often corrupted. In this case the recorded forms include Worsall, Worsell, Worshall, and Warstall, the latter being seemingly found only in County Durham.
Not sure about this: our family story is that "a worstall" was a barn builder, an occupational name like Smith, Miller or Thatcher. But then such family stories are rather like urban myths: only very occasionally true.
The above explanation does fit though, given the Yorkshire origins of that part of the lineage that the name comes from.
As for the "very unusual", yes, it is, very. With this specific spelling there\’s perhaps a few hundred in the US: in the UK precisely four (or at least, as far as I know that\’s so). The parentals and then, when we\’re in country at least, my brother and myself. And that\’s it.