The 2010 Honolulu special mayoral election was held on September 18, 2010. The election coincided with Hawaii's primary election. The winner of the election, Peter Carlisle, filled the unexpired term of former Democratic Honolulu Mayor Mufi Hannemann, who resigned on July 20, 2010 to run in the 2010 election for Governor of Hawaii. Honolulu Managing Director Kirk Caldwell was acting Mayor of Honolulu on July 20, 2010, following Hannemann's resignation, until the special election was held.