 Appointed Lord Lieutenant of Cumberland and Westmorland in 1738, he was, by virtue of that office, responsible for the defense of those counties during the Rising of '45.However, he remained at his sister Elizabeth's house at Byram, Yorkshire during that period, Lowther Hall being uninhabitable due to alterations, and left military affairs largely in the hands of Sir George Fleming, Bt, Bishop of Carlisle.He died at Byram on 7 March 1751 and was buried on 18 March at Lowther Hall.