GREENSBURG, IN--(Marketwire - Jun 24, 2011) - Archie M. Brown, President and CEO of MainSource Financial Group (NASDAQ: MSFG), announced today that Charles J. Thayer was appointed to the Board of Directors of MainSource at its Board of Directors Meeting held on June 20, 2011, to be effective with the Board of Directors meeting to be held on July 18, 2011. At that time Mr. Thayer will also be appointed to the Board of Directors of MainSource Bank.