"It has been one of the highest honors and privileges of my life to have served the people of Illinois in the United States Senate. In a state that represents the crossroads of a nation, I have met so many men and women who've taken different journeys, but hold common hopes for their children's future.

"It is these Illinois families and their stories that will stay with me as I leave the United States Senate and begin the hard task of fulfilling the simple hopes and common dreams of all Americans as our nation's next President,'" Obama said in a statement.