William Legge, 4th Earl of Dartmouth

William Legge, 4th Earl of Dartmouth FRS, SA (29 November 1784 – 22 November 1853), styled The Honourable William Legge until 1801 and Viscount Lewisham between 1801 and 1810, was a British peer.

Background Dartmouth was the son of George Legge, 3rd Earl of Dartmouth, by Lady Frances, daughter of Heneage Finch, 3rd Earl of Aylesford. Heneage Legge and Arthur Legge were his younger brothers.

Career Dartmouth was returned to Parliament as one of two representatives for Milborne Port at a by-election in January 1810. However, in November of the same year he succeeded his father in the earldom and took his seat in the House of Lords. He was admitted a Fellow of the Royal Society on 7 November 1822. He was also a Fellow of the Society of Antiquaries.

Family Lord Dartmouth was twice married. He was succeeded in the earldom by his only child from his first marriage.

Other Dartmouth was the litigant in the trust law case of Howe v Earl of Dartmouth (1802) 7 Ves 137.