Elva Mary O'Sullivan
- Born: ca. 1923, Leeton, New South Wales, Australia
- Marriage (1): Kenneth Douglas Halsall in 1946 in Leeton, New South Wales, Australia
- Died: 2017, England about age 94
At the time of her mother's death in 1963 she living in Somerset, England with her husband.
Elva married Kenneth Douglas Halsall, son of Douglas Halsall and Florence Adams, in 1946 in Leeton, New South Wales, Australia. (Kenneth Douglas Halsall was born on 19 Dec 1921 in West Derby, Lancashire, England and died on 18 Jun 2014 in Newport Pagnell, , Buckinghamshire, England.)