KOIN, which first reported his upcoming release, said Gillmore will remain under supervision until 2034 and could be sent back to prison if he violates his parole.
A judge in the Edens case sentenced Gillmore to at least 30 years in prison with a 60-year maximum. But a parole board cut his sentence in half in 1988, the year after he was convicted.
Danielle Tudor, who has said she was a teenager when Gillmore raped her in 1979, has spoken out against his release.
"If he had been able to have been charged for all the rapes he committed, he'd never be getting out," Tudor told KOIN.
Gillmore has been classified as a sex offender at the lowest risk of reoffending. He will have to register as a sex offender for the rest of his life due to his rape conviction, but the classification means the state and county aren't required to notify surrounding residents that he's living near them.
His victims are angered that Gillmore isn't considered a high-risk sex offender, which would require notification to the community regarding wherever he lives or moves to.
The Oregonian reported that Tudor said she didn't understand why he was being classified as a low-level sex offender.
"He was designated as a dangerous offender at trial," Tudor said.