James Cecil, 4th Earl of Salisbury (1666–1694), until 1683 known by the courtesy title of Viscount Cranborne, was an English peer, nobleman, and politician.
A courtier of King James II, during the Glorious Revolution of 1688 he commanded a regiment in support of the king. Afterwards he was imprisoned in the Tower of London for some twenty-two months, eventually being charged with high treason. Although released in October 1690 following a general pardon, he died in 1694 at the age of twenty-eight.
Baptised on 25 September 1666, Salisbury was one of the ten children of James Cecil, 3rd Earl of Salisbury KG, by his marriage in 1661 to Lady Margaret Manners, a daughter of John Manners, 8th Earl of Rutland. He was educated at St John's College, Cambridge, and as his father's eldest surviving son succeeded him when he died in May 1683. In 1656 Thomas Russell purchased half of Witley Park in Surrey for Cecil's father-in-law and a half share therefore passed on marriage of each daughter, one of whom was Cecil's wife.
On 13 July 1683, at the age of sixteen, the new Earl of Salisbury married Frances Bennett (1670–1713), a daughter of Simon Bennett, of Buckinghamshire. Bennett, who by the time of this marriage had died, had left three daughters, and in his will had left them each £20,000, subject to their not marrying before the age of sixteen or without the consent of those he named, with the proviso that the legacy of a daughter doing so was to be reduced to £10,000. Frances Bennett married Salisbury before she was sixteen, but with the consent of the Executors to the will, and this later led to litigation.