William Legge, 4th Earl of Dartmouth FRS, SA (29 November 1784 – 22 November 1853),[1] styled The Honourable William Legge until 1801 and Viscount Lewisham between 1801 and 1810, was a British peer.

[2] Dartmouth was returned to Parliament as one of two representatives for Milborne Port at a by-election in January 1810.

[3] However, in November of the same year he succeeded his father in the earldom and took his seat in the House of Lords.

[2] Like his father before him, Dartmouth served as an officer in the Staffordshire Militia, and was promoted to command it with the rank of Colonel in 1812.

Lord Dartmouth remained a widower until his death in November 1853, aged 68.