http://en.wikipedia.org/wiki/Lists_of_Presidents_of_the_United_States_by_place_of_birth
They have it as this hospital:
Kapi’olani Medical Center for Women & Children, Honolulu, Hawaii
Interesting ... They have he and Chester Arthur listed as British Subjects at birth.
This from Fact check Org, as an Adult, He was Kenyan Citizen:
Corrected (Sep. 3, 2009): Our original article incorrectly stated that then-Sen. Obama lost his Kenyan citizenship on Aug. 4, 1982. The correct date is Aug. 4, 1984. The Kenyan Constitution required Obama to choose whether to keep either his U.S. or Kenyan citizenship upon his 21st birthday, which was in 1982. But we initially missed that the Constitution provided him a two-year window for making that choice. So Obama did not lose his Kenyan citizenship until his 23rd birthday in 1984. We have updated the item to reflect this.
So, Michelle Obama was correct. As an Adult he was a Kenyan Citizen.
Chester A. Arthur political opponents accused him of not being a Natural Born citizen. They believed that he was born one year before his father was a U.S. citizen. They wanted him declared ineligible under Article 2 of the Constitution. His opponents were unable to provide any proof(birth certificate) however and were not able to have him declared ineligible. Whether or not Arthur was a Natural Born citizen is still unknown due to lack of records. But we KNOW that obama’s father was a foreign national, and thus making obama ineligible to be the President. As there has been no laws passed sinced Arthur was President that changed the meaning of Natural Born citizen, we must conclude that the meaning has not changed. Both parents must be U.S. citizens to be declared Natural Born.