Police said Phillip Garrido, 58, held her the entire time as a virtual slave, sheltered from the outside world in tents, sheds and outbuildings in his backyard in suburban Antioch.
"None of the children have ever been to school, they've never been to a doctor," El Dorado County Undersheriff Fred Kollar said. "They were kept in complete isolation in this compound, if you will."
There was electricity from electrical cords, rudimentary outhouse, rudimentary shower, "as if you were camping," he said.
Prison officials said Garrido later admitted the kidnapping after meeting with his parole officer. He brought Dugard and the two children, ages 11 and 15, to the meeting.
Garrido and his wife Nancy Garrido, 54, were arrested for investigation of kidnapping and conspiracy on Wednesday, police said.
Phillip Garrido is also being held for investigation of rape by force, lewd and lascivious acts with a minor and sexual penetration, said Jimmie Lee, a spokesman for the Contra Costa Sheriff's Department.
Phillip Garrido has a conviction for rape by force or fear and was paroled from a Nevada state prison in 1999, according to the California Department of Corrections and Rehabilitation.
Dugard was in good health when she came into a San Francisco Bay area station. She was reunited Thursday with her mother, who was overjoyed to learn the ordeal was over and the daughter she feared dead was actually alive and well.
Dugard's stepfather, the last person to see her in 1991 and a longtime suspect in the case, said he was overwhelmed after doing everything he could to help find her.
"It broke my marriage up. I've gone through hell, I mean I'm a suspect up until yesterday," Carl Probyn, 60, told The Associated Press at his home in Orange, Calif.
California corrections officials said they called in Garrido for questioning Wednesday after receiving a report that he was seen with two small children at the University of California, Berkeley.
"The diligent questioning and follow-up by the parolee's agent of record led to Garrido revealing his kidnapping of the adult female," the department said in a statement. "It was further revealed by Garrido that she was Jaycee Lee Dugard, and that the children were his."
A house in the city of Antioch was cordoned off with police tape as it was searched by FBI agents and the El Dorado County Sheriff's Department.
Neighbor Helen Boyer, 78, described the Garridos as nice and friendly and said they cared for Phillip Garrido's elderly mother.
"If I needed something, they would be the first I would call on," Boyer said.
Witnesses reported that a vehicle with two people drove up to Dugard and abducted her while her stepfather watched on June 10, 1991.
Probyn said he saw someone reach out and grab her before the car sped away.
"As soon as I saw the door fly open, the driver's door, I jumped on my mountain bike and I tried to get to the top of the hill but I had no energy. I rode back down and yelled at my neighbor, 911!" he recalled.
Probyn said his wife, from whom he is separated, was devastated by the kidnapping. He said for 10 years after the crime, she would take a week off work at Christmas and on the anniversary of the abduction and spend the time crying at home.
The case attracted national attention and was featured on TV's "America's Most Wanted," which broadcast a composite drawing of a suspect seen in the car.
Probyn eventually lost hope that he would ever see his stepdaughter alive. He said he was struggling to understand why Dugard didn't come forward earlier.
"I have a million questions, but I'm just delighted," he said. Lovell said investigators have been working the case consistently since the abduction and new leads had surfaced over time.
"You bet it's a surprise. This is not the normal resolution to a kidnapping," he said.
The Associated Press as a matter of policy avoids identifying victims of alleged sexual abuse by name in its news reports. However, Dugard's disappearance had been known and reported for nearly two decades, making impossible any effort to shield her identity now.
Associated Press Writers Paul Elias and Terry Collins in San Francisco, Gillian Flaccus in Orange, Calif., and Brooke Donald in Antioch, Calif., contributed to this report.