Wikipedia , Barack Obama:
Barack Obama was born at the Kapi’olani Medical Center for Women & Children in Honolulu, Hawaii, United States,[6]
Footnote:[6] Maraniss, David (August 24, 2008). “Though Obama Had to Leave to Find Himself, It Is Hawaii That Made His Rise Possible”. Washington Post. http://www.washingtonpost.com/wp-dyn/content/article/2008/08/23/AR2008082301620.html. Retrieved October 27, 2008.
I wonder how the post determined the hospital where he was born.
Probably asked Neil Abercrombie...