Former child soldier James Bior, pictured below in camouflage fatigues, came to America as one of the Lost Boys, a group of about 3500 young refugees who became separated from their families when soldiers from northern Sudan raided their villages. 

Related: South Sudan is world's newest nation.

John Brecher / msnbc.com

James Bior leads a song in memory of John Garang, the late leader of the Sudan People's Liberation Army, during a celebration for new nation of South Sudan, held at the Church by the Side of Road in Tukwila, Washington.

Bior drifted around Ethiopia and southern Sudan and was drafted by the Sudan People's Liberation Army at the age of 12 in 1991. He said he trained and fought with SPLA until its leader John Garang visited his group and sent away the underage soldiers.  Bior then lived for several years at the Kakuma refugee camp in Kenya, before joining his cousin Mawut Mayen in the Seattle area. Here's a recent interview with Mayen, who now works as an industrial engineer at Boeing:

Here's more about Mawut Mayen, here's a slideshow from South Sudan, and below are more images from the celebration in Tukwila, Wash.:

John Brecher / msnbc.com

Martha Duot cheers during a celebration for the new nation of South Sudan, held at the Church by the Side of Road in Tukwila, Washington. Duot's father is from Sudan and her mother is from Kenya, and she moved to the United States three years ago. About South Sudan, she said "I want to go back and see my country."

John Brecher / msnbc.com

Dancers perform in the style of the Nuer people of South Sudan during the celebration.

John Brecher / msnbc.com

Abraham Nuul Dengdit carries flags for the U.S. and the new nation of South Sudan into the Church by the Side of the Road in Tukwila, Wa. before the party.