The Jerningham Baronetcy, of Cossey in the County of Norfolk, was a title in the Baronetage of England. It was created on 16 August 1621 for Henry Jerningham. The 5th Baronet married Mary Plowden, only daughter of Mary Plowden, sister of John Paul Stafford-Howard, 4th Earl of Stafford and de jure 5th Baron Stafford. He was succeeded by his son, the sixth Baron. In 1807 the claim to the barony of Stafford, which had been under attainder since 1680, passed to him through his mother. He died in 1809 when the baronetcy and the claim to the barony passed to his son, the seventh Baronet. He petitioned the House of Lords for a reversal of the attainder of the barony of Stafford and for a writ of summons to Parliament. In 1824 the attainder was reversed and the following year he was summoned to the House of Lords as the eighth Baron Stafford. He was succeeded by his eldest son, the ninth Baron and eighth Baronet. He represented Pontefract in the House of Commons. He was succeeded by his nephew, the tenth Baron. On the death of the latter's brother, the eleventh Baron and tenth Baronet, the two titles separated. The barony, which could be inherited through female lines, was passed on to the late Baron's nephew Francis Edward Fitzherbert, who became the twelfth Baron. He was the son of Emily Charlotte Fitzherbert and her husband Basil Thomas Fitzherbert. The baronetcy, which could only be inherited through male lines, was passed on to Henry William Stafford Jerningham, the eleventh Baronet. On his death in 1935 the baronetcy became extinct. The seat of the Jerningham family was Costessey Hall in Norfolk.
Jerningham baronets, of Cossey (1621)
Sir Henry Jerningham, 1st Baronet, married Eleanor Throckmorton
Sir Henry Jerningham, 2nd Baronet , married Mary Hall
Sir Francis Jerningham, 3rd Baronet , married Anne Blount
Sir John Jerningham, 4th Baronet , married Margaret Bedingfield, died without issue
Sir William Jerningham, 6th Baronet , would have been 7th Baron Stafford but for the attainder, which was reversed in 1824; married Frances Dillon, daughter of the 11th Viscount Dillon
George William Jerningham, 8th Baron Stafford, 7th Baronet , was restored as eighth Baron Stafford in 1824; married Frances-Henrietta Sulyarde