It was created in 1766 for Edward Turnour, 1st Baron Winterton, who represented Bramber in the House of Commons.

Lord Winterton's great-great-great-grandson (the titles having descended from father to son), the sixth Earl, was a Conservative politician.

He represented Horsham in the House of Commons for almost fifty years and served as Under-Secretary of State for India and as Chancellor of the Duchy of Lancaster.

In 1952 he was created Baron Turnour, of Shillinglee in the County of Sussex, in the Peerage of the United Kingdom.

The titles of the earldom and original barony (despite being in the Peerage of Ireland) referred to the village of Winterton-on-Sea in Norfolk, where the Turnour family also owned land.