Cavendish-Bentinck family, Dukes of Portland

Sir Charles Cavendish, third son of Sir William Cavendish of Chatsworth (Derbyshire), acquired Welbeck (Nottinghamshire) in 1598 and Bolsover (Derbyshire) in 1608, both from the Talbot family. His second wife, Catherine, Baroness Ogle, brought the Bothal (Northumberland) estates. Their son, William Cavendish, was created Earl (1628), Marquess (1643) and Duke (1665) of Newcastle. Following the death of the 2nd Duke in 1691 these Cavendish estates passed to his daughter, Margaret, wife of John Holles, 4th Earl of Clare. Lord Clare was created Duke of Newcastle in 1694. On his death in 1711 the Clare estates and a portion of the Cavendish estates passed to his nephew, Thomas Pelham, created Duke of Newcastle in 1715, but the bulk of the Cavendish lands, together with the manor of Marylebone (Middlesex) and Wimpole (Cambridgeshire) passed to his daughter Henrietta, who married Edward Harley, later 2nd Earl of Oxford.

Lord Oxford sold Wimpole, and on his death in 1741 the Harley estates in Herefordshire (Brampton Bryan etc.) passed to a cousin, but his widow continued in possession of the Welbeck estates, which on her death in 1755 passed to her daughter, Lady Margaret Cavendish Harley. Lady Margaret married William Bentinck, 2nd Duke of Portland, and her estates were inherited by the 3rd Duke on her death in 1785.

Hans Willem Bentinck (1649-1709), an associate of King William III, was created Earl of Portland in 1689 and acquired extensive estates in Buckinghamshire (Bulstrode Park), Hertfordshire (Theobalds), Cumberland, Middlesex (Soho) and elsewhere, plus, in his mother's name, a large estate in Ireland. His son, Viscount Woodstock, later 2nd Earl and from 1716 1st Duke of Portland, married in 1704 a daughter of the 2nd Earl of Gainsborough, through whom came a moiety of the Titchfield (Hampshire) estates formerly belonging to the Wriothesley Earls of Southampton. The Bentinck estates were, however, largely disposed of by sale in the 18th and early 19th centuries.

Lord Titchfield, later 4th Duke of Portland, married in 1794 Henrietta Scott, heiress of the Balcomie (Fife) estate, whose trustees also acquired for her the Cessnock, Dean and Kilmanock estates in Ayrshire. The 4th Duke sold Balcomie but increased the Ayrshire estates by purchase, notably Fullarton in 1803. The Langwell (Caithness) estate was acquired by the 5th Duke between 1857 and 1869. On the death of the 5th Duke in 1879 most of the estates passed to the cousin who succeeded him as 6th Duke, but part of the Ayrshire estates were divided between the 5th Duke's sisters, Lady Ossington and Lady Howard de Walden, the latter also inheriting the Marylebone property.

Estates in 1883: 43,036 acres in Nottinghamshire; 12,337 acres in Northumberland; 8,074 acres in Derbyshire; 903 acres in Lincolnshire; 591 acres in Norfolk; 9 acres in Worcestershire; 5 acres in Buckinghamshire; 101,000 acres in Caithness; 17,244 acres in Ayrshire; worth a total of £88,350 a year.