Arms: Quarterly: 1st, Sable, a Fess between three Lambs passant Argent (Lambton); 2nd, Argent a Fess Gules between three Popinjays Vert, collard Gules (Lumley); 3rd, Argent, an Escutcheon Sable, within an Orle of eight Cinquefoils Gules (Hedworth); 4th, Argent, three Cinquefoils Gules (D'Arcy). Crests: 1st: A Ram's Head cabossed Argent, attired Sable (Lambton); 2nd: a Woman's Head affrontée, couped at the breast, proper, hair flowing Or, wreathed about the temples with a Garland of Cinquefoils Gules, pierced Or (Hedworth); 3rd: out of a Ducal Coronet Or, an Antelope's Head, isuant, winged Argent, attired and barbed Or (D'Arcy). Supporters: Dexter: a Lion Gules, ducally gorged Or, supporting a Flagstaff Or, therefrom flowing a Banner Azure, charged with a Cross-Potence; Sinister: a Lion Azure, ducally gorged Or, supporting a Flagstaff Or, therefrom flowing a Banner Azure, charged with a Lion passant guardant Or.
He was succeeded by his only surviving son, the second Earl. He served as Lord-Lieutenant of County Durham from 1854 to 1879. On his death, the titles passed to his eldest twin son, the third Earl. He was Lord-Lieutenant of County Durham from 1884 to 1928 and was made a Knight of the Garter in 1909. He died childless and was succeeded by his younger twin brother, the fourth Earl. He represented South Durham and South East Durham in the House of Commons. His grandson, the sixth Earl, was a Conservative politician. He disclaimed his peerage titles shortly after succeeding his father in 1970, but improperly continued to style himself Viscount Lambton. As of 2014, the titles are held by his only son, the seventh Earl, who succeeded in 2006. Before succeeding to the earldom, he styled himself Lord Durham to avoid confusion with his father.
The ancestral seats of the Lambton family are Lambton Castle, near Chester-le-Street, County Durham, and Fenton Estate, near Wooler, Northumberland. The latter, about 2,000 acres (8.1 km2), was put up for sale in 2015 with a guide price of £10,000,000.[3]