Mervyn Tuchet, 4th Earl of Castlehaven; 14th Baron Audley; 2nd Baron Audley of Hely (d. 2 November 1686), was the son of Mervyn Tuchet, otherwise Audley, 2nd Earl of Castlehaven and his first wife, Elizabeth Barnham (1592 - about 1622).
He married Mary Talbot (buried 15 Mar 1710/1), daughter of John Talbot, 10th Earl of Shrewsbury (before 1601-1654) and of his wife née Mary Fortesque.
They had two children:
- Mary
- James (-1700)
{| border="2" align="center"
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|width="30%" align="center"|Preceded by:
James Tuchet
|width="40%" align="center"|Earl of Castlehaven
|width="30%" align="center"|Followed by:
James Tuchet
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