The State Department heavily promoted international activities to mark the occasion, using the official blog and Twitter feed.
"I don't think she realizes how what she has done has made what I am doing partially possible,” Obama said of Clinton, according to the White House transcript. "So with all the respect and admiration that I can give to her, I will be wherever she needs me to be, whenever she needs me to be there."
Clinton ran against President Obama in the 2008 Democratic primary and plans to retire from her position heading the State Department after the 2012 election.
"She has been an outstanding — should I say that again? An outstanding secretary of State," Michelle Obama said. "And she has been an inspiration to women and girls around the world."