Lyneham in the parish of Yealmpton in Devon, is an historic estate. The surviving grand mansion house known as Lyneham House is a grade I listed building. It was built c.1699-1703 by Sir Courtenay Croker (died 1740), MP for Plympton Morice in 1699. A drawing of Lyneham House dated 1716 by Edmund Prideaux (1693–1745) of Prideaux Place, Padstow, Cornwall, survives at Prideaux Place. It shows formal gardens in front with flanking pavilions and an orangery.
The estate was, after Crocker's Hele, in the parish of Meeth, the second earliest known Devonshire home of the Croker family, one of the most ancient in Devon according to "that old saw often used among us in discourse", the traditional rhyme related by Prince (died 1723):
"Crocker, Cruwys, and Coplestone,
When the Conqueror came were at home"
The last male of the Crocker family of Lyneham was Courtenay Crocker (died 1740), several times MP for Plympton. The Cruwys family in 2014 still resides in its ancient manor house at Cruwys Morchard where, despite the traditional rhyme which seeks to give it Anglo-Saxon origins, it is first recorded in the reign of King John (1199–1216), or possibly a little earlier. The senior branch of the Copleston family died out in the male line in 1632, but the Coplestons of Bowden in the parish of Ashprington survived a further century until the death without children of Thomas Copleston (1688–1748), MP, whose heirs in 1753 sold Bowden to William Pollexfen Bastard of Kitley.
Lynham is not listed as an estate or manor in the Domesday Book of 1086, which does however list the manor of Yealmpton, one of 72 royal manors or other holdings in Devonbelonging to King William the Conqueror. It is likely that the one hide within that manor which the Domesday Book states the king had granted in frankalmoinage to "the clergy of the same village" (clerici ei(us)d(em) villae) was Lynham. The mother church of these clergy was Salisbury Cathedral in Wiltshire.