Sarah Ann Hanson, née Murray, was JW's daughter-in-law. She was the daughter of Benjamin Patrick Murray, a bootmaker of Halesworth, Suffolk. She married Charles James Whistler Hanson on 25 June 1896. JW did not attend the wedding which took place soon after the death of Beatrix Whistler and the only witness was Sarah Hanson's brother Francis, then a medical student at Guy's Hospital. The Hansons had two, possibly three children, the first of whom died young in March 1908. The second, Adrian survived.
Her photograph is in the collection of Glasgow University Library.
Birth and Marriage certificates, Family Records Centre, London; information from family descendant.