Mitchell, whose name both as explorer and Surveyor-General looms large in our history, was born at Craigend, Stirlingshire, in 1792. He was the son of John Mitchell of Grangemouth, and his mother was a daughter of Alexander Milne of Carron Works. When he was but sixteen, young Mitchell joined the army of the Peninsula as a volunteer. Three years later he received a commission in the 95th Regiment or Rifle Brigade. He was employed on the Quartermaster General's staff at military sketching; and he was present in the field at Ciudad Rodrigo, Badajoz, Salamanca, the Pyrenees, and St. Sebastian. After the close of the war he went to Spain and Portugal to survey the battlefields. He received promotion to a Lieutenancy in 1813. He served in the 2nd, 54th, and 97th Regiments of foot, and was promoted to be Captain in 1822, and Major in 1826. His appointment as Surveyor-General of New South Wales, as successor to John Oxley, took place in 1827, when he at once assumed office, and started energetically to lay out and construct roads, then the urgent need of the new colony. His strong personality, and the energy and thoroughness he displayed in all his undertakings, combined with his many gifts as draughtsman, surveyor and organizer, proved to be of peculiar service to the colony at that period of its existence. There was a vast unknown country surrounding the settled parts, awaiting both discovery and development, and Mitchell's inclinations and talents being strongly directed towards geographical discovery, the office of Surveyor-General that he held for so long was the most appropriate and advantageous appointment that could have been given him in the interests of the colony.