Flavia Wagner, 35, was released by kidnappers after 105 days in captivity, according to North Carolina-based Samaritan's Purse. Wagner was working as the group's education program manager in Darfur.
"She said she is looking forward to being reunited with her family in the United States," according to a statement on the group's website, which also said its staff has seen Wagner.
"People around the world have been praying for her safety and her release," added Graham, son of famed evangelist the Rev. Billy Graham. "Today, those prayers have been answered."
The group had no details on her release.
The Associated Press didn't identify Wagner by name but reported today that a female American aid worker kidnapped months ago in Darfur was "liberated by police." Reuters said she was released.
"She's been released this morning. She is in good health," a foreign ministry spokesman, Moawia Osman, told Reuters. "Right now she is in the Wali's [governor's] residence in Nyala."
Wagner and two other aid workers, both Sudanese men, were kidnapped May 18 when their two-vehicle group was stopped by eight armed men, Samaritan's Purse said in a release. The two Sudanese men were released a week later unharmed, the group said.
Wagner was part of a 10-member team conducting educational assessments in the area. Born in Cincinnati, she has family in Southern California and had been living outside of New York City before she went to Sudan.