Ulrich II of East Frisia, was count of East Frisia, (6 July 1605 – Aurich, 1 November 1648) was the fifth child and the third son of Enno III, Count of East Frisia and Anna of Holstein-Gottorp. He inherited the East Frisia after the unexpected death of his brother Rudolf Christian on 17 April 1628. He reigned during the Thirty Years' War. East Frisia did not participate in the war, but general Ernst von Mansfeld quartered his troops in East Frisia, causing great distress. The only exception was Emden because of the recently completed city wall, the city of Emden was protected against foreign troops.