Baron Southampton, of Southampton in the County of Southampton, is a title in the Peerage of Great Britain. It was created in 1780 for the soldier and politician Charles FitzRoy. He was the third son of Lord Augustus FitzRoy, second son of Charles FitzRoy, 2nd Duke of Grafton, while Prime Minister Augustus FitzRoy, 3rd Duke of Grafton was his elder brother. Lord Southampton was also the great-great-grandson (through an illegitimate line) of King Charles II by his mistress Barbara Palmer, 1st Duchess of Cleveland. The Southampton title had previously been created for Charles FitzRoy, eldest natural son of Charles II and the Duchess of Cleveland and the elder brother of Henry FitzRoy, 1st Duke of Grafton, but had become extinct in 1774 on the death of his son William FitzRoy, 3rd Duke of Cleveland and 2nd Duke of Southampton, six years before the creation of the barony of Southampton.
The first Baron Southampton's grandson, the third Baron, notably served as Lord-Lieutenant of Northamptonshire from 1867 to 1872. Lord Southampton was succeeded by his eldest son, the fourth Baron. He held the title for 86 years and 144 days, the fourth longest time anyone has held a peerage (the others being the 7th Marquess Townshend 88 years, the 13th Lord Sinclair, 87 years, and the 3rd Baron Montagu of Beaulieu (86 years and 155 days)). His son, the fifth Baron, disclaimed the title on 16 March 1964. Since 2015 the title has been held by his grandson, the seventh Baron, who, as a descendant of the second Duke of Grafton, is also in remainder to this peerage and its subsidiary titles.
Two other members of this branch of the FitzRoy family also gained distinction. The Hon. Henry FitzRoy, second son of the second Baron, was a politician. The Hon. Edward FitzRoy, second son of the third Baron, served as Speaker of the House of Commons from 1928 until his death in 1943. In 1943 his widow was created Viscountess Daventry in his honour.
Barons Southampton (1780)
- Charles FitzRoy, 1st Baron Southampton (1737–1797)
- George Ferdinand FitzRoy, 2nd Baron Southampton (1761–1810)
- Charles FitzRoy, 3rd Baron Southampton (1804–1872)
- Charles Henry FitzRoy, 4th Baron Southampton (1867–1958)
- Charles FitzRoy, 5th Baron Southampton (1904–1989) (disclaimed 1964)
- Charles James FitzRoy, 6th Baron Southampton (1928–2015)
- Edward Charles FitzRoy, 7th Baron Southampton (b. 1955)
The heir apparent is the present holder's son Hon. Charles Edward Millett FitzRoy (b. 1983).
- Kidd, Charles, Williamson, David (editors). Debrett's Peerage and Baronetage (1990 edition). New York: St Martin's Press, 1990,
- Leigh Rayment's Peerage Pages