Obama praises courage of Rosa Parks
"(I)n a single moment, with the simplest of gestures, she helped change America - and change the world," he said of Parks, the first African-American to be honoured with a life-size statue in the Capitol.
Sojourner Truth, one of the first black women to fight against slavery in the US, has a bust located in the Capitol Visitors Center.
On Dec 5, 1955, on a public bus in Montgomery, Alabama, the 42-year-old Parks challenged the prevailing segregation laws by refusing to give up her seat to a white man.
For that, she was arrested, sent to jail and fined $40.
Parks, a seamstress by trade, was an active member of the NAACP and her arrest resulted in a boycott lasting 381 days against the Montgomery bus system organized by Martin Luther King Jr.
In 1998, the US Congress authorized Parks to receive the Medal of Honor, the main decoration that the legislative body bestows on civilians.
On Dec 1, 2005, President George W. Bush signed a law urging Congress to add a statue of Rosa Parks to the Capitol collection.
The greatest honour that can be done to Parks' memory is "to carry forward the power of her principle and a courage born of conviction", Obama said Wednesday.
Attending the ceremony at the Capitol were several of Parks' relatives and a number of leaders of Congress.
Parks died in 2005 of natural causes.