Detectives said the girl is now 7 years old and living with family members in Las Vegas, CNN reported.
"We have found the child, Madison," Sheriff Tony DeMeo said. "She's safe. The detectives say she is in good condition."
Detectives had been looking for the girl since they learned of the videotape, believed to have been made four years ago. An older girl who was also shown on the tape -- apparently in images captured without her knowledge -- has also been located.
Police were seeking a man identified as Chester Arthur Stiles of Pahrump, Nev. Detective David Boruchowitz said Stiles is believed to have known friends of friends of the girl's family.
Stiles was also being sought on sexual assault charges. DeMeo said he resembles a man seen on the videotape.
Nye County detectives received the tape from a man who said he found it in the desert. Darren Tuck has been charged with possession of child pornography and of exhibiting it, charges he denies.