Viscount Palmerston was a title in the Peerage of Ireland created on March 12, 1723. Upon the death of the third Viscount (who served as Prime Minister of the United Kingdom), the title became extinct.

Viscounts Palmerston (1723)

• Henry Temple, 1st Viscount Palmerston (c. 1673-1757)
• Henry Temple, 2nd Viscount Palmerston (1739-1802)
• Henry John Temple, 3rd Viscount Palmerston (1784-1865)

Reference

• PALMERSTON, HENRY JOHN TEMPLE, 3RD VISCOUNT (http://67.1911encyclopedia.org/P/PA/PALMERSTON_HENRY_JOHN_TEMPLE.htm), 1911 Encyclopedia Britannica