Recorded in several forms including Costall, Costell, Costol, Costle, and possibly others, this is an English surname. It is well recorded in the surviving church registers of the city of London from about the time of King Henry V111 (1510 - 1547), and is almost certainly residential. This is to say that it originates from a 'place', the question is where and what is the place? There is nothing quite like any of the known surname spellings in the gazetters and maps of the past three centuries. From this we have to deduce that either the place itself has disappeared, which has happened quite regularly, or the surname is a transposed spelling of something else. In this case we believe the latter to be correct, and that this name is a dialectal form of the popular surnames Castle or Castel, or possibly for some name holders a short form of the Irish Costello. Examples of recordings include Elizabeth Costell who married John Pont at St Margarets Westminster, on May 5th 1550, and later that of John Costell on June 10th 1717, and the same man, but now recorded as John Costall, at the church of St Botolphs without Aldgate, in the city of London, on July 26th 1719.