[2] His father was Mark Milbanke of Chirton, Northumberland (died 1677) a Newcastle on Tyne merchant and hostman who was Sheriff of the city in 1638, and Mayor in 1658 and 1672, and whose marriage brought him an estate at Halnaby, near Darlington, North Yorkshire.

The third Baronet was High Sheriff of Northumberland 1685 and Member of Parliament for Richmond.

The sixth Baronet sat as Member of Parliament for County Durham.

He married Judith Noel and changed his surname in 1815, but he died leaving only a daughter, Annabella, who married the poet Lord Byron, and so he was succeeded by his nephew.

Halnaby Hall was demolished in 1952 following the death of the twelfth and last Baronet.