Baron Dover is a title that has been created three times, once in the Peerage of England

Peerage of England

The Peerage of England comprises all peerages created in the Kingdom of England before the Act of Union in 1707. In that year, the Peerages of England and Scotland were replaced by one Peerage of Great Britain....

, once in the Peerage of Great Britain

Peerage of Great Britain

The Peerage of Great Britain comprises all extant peerages created in the Kingdom of Great Britain after the Act of Union 1707 but before the Act of Union 1800...

 and once in the Peerage of the United Kingdom

Peerage of the United Kingdom

The Peerage of the United Kingdom comprises most peerages created in the United Kingdom of Great Britain and Ireland after the Act of Union in 1801, when it replaced the Peerage of Great Britain...

. All three creations are now extinct.

The first creation came in the Peerage of England in 1685 when Henry Jermyn was made Baron Dover. In 1703 he also succeeded his elder brother as Baron Jermyn

Baron Jermyn

Baron Jermyn, of St Edmundsbury, was a title in the Peerage of England. It was created in 1643 for Henry Jermyn, with remainder, failing heirs male of his own, to his nephews. In 1660 he was further honoured when he was made Earl of St Albans, with normal remainder to the heirs male of his body...

. For more information on this creation, see the latter title.

The second creation came in the Peerage of Great Britain in 1788 when then soldier General Sir Joseph Yorke

Joseph Yorke, 1st Baron Dover

General Joseph Yorke, 1st Baron Dover KB, PC , styled The Honourable Joseph Yorke until 1761 and The Honourable Sir Joseph Yorke between 1761 and 1788, was a British soldier, diplomat and Whig politician....

 was made Lord Dover, Baron of the Town and Port of Dover, in the County of Kent. He was the third son of Philip Yorke, 1st Earl of Hardwicke

Philip Yorke, 1st Earl of Hardwicke

Philip Yorke, 1st Earl of Hardwicke PC was an English lawyer and politician who served as Lord Chancellor. He was a close confidant of the Duke of Newcastle, Prime Minister between 1754 and 1756 and 1757 until 1762....

. The peerage became extinct on Lord Dover's death in 1792.

The third creation came in the Peerage of the United Kingdom in 1831 when the politician George Agar-Ellis

George Agar-Ellis, 1st Baron Dover

George James Welbore Agar-Ellis, 1st Baron Dover PC FRS FSA was a British politician and man of letters. He was briefly First Commissioner of Woods and Forests under Lord Grey between 1830 and 1831.-Background and education:...

 was created Baron Dover, of Dover in the County of Kent. He was the only son of Henry Ellis, 2nd Viscount Clifden

Henry Ellis, 2nd Viscount Clifden

Henry Welbore Ellis, 2nd Viscount Clifden SA , styled The Honourable Henry Agar between 1776 and 1789, was an Irish politician.-Background:...

. For more information on this creation, see Viscount Clifden

Viscount Clifden

Viscount Clifden, of Gowran in the County of Kilkenny, was a title in the Peerage of Ireland. It was created on 12 January 1781 for James Agar, 1st Baron Clifden. He had already been created Baron Clifden, of Gowran in the County of Kilkenny, in 1776, also in the Peerage of Ireland...

.