South Sudan is the world's newest nation, officially breaking away from Sudan after two civil wars fought over five decades.
In the new country capital, Juba, residents are dancing in the streets, banging on drums and chanting the name of the country's president, Salva Kiir.
South Sudan earned independence at 12:01 a.m. local time Saturday, after voting overwhelmingly in January to form its own country.
That vote was guaranteed in a 2005 peace deal that ended the most recent north-south war.
Later Saturday, world leaders will attend a celebratory ceremony. U.N. Secretary-General Ban Ki-moon already has arrived. Former U.S. Secretary of State Colin Powell will also attend, as will Sudan President Omar al-Bashir.