Corrected By Corrections: The 5 Day Difference
Calculating prison terms and release dates may more easily lead to errors in numbers, but when it comes to who has the honor of being California's longest-incarcerated woman, that distinction does indeed belong to Susan Atkins, the former Manson family member who is currently asking for a compassionate release from her life sentence.
In an email to LAist from Department of Corrections and Rehabilitation Spokeswoman Terry Thornton, it seems it comes down to a mere five days; small time math for us, but a bigger deal if it's your prison term:
Inmate Atkins was received onto California's death row on April 23, 1971 at California Institution for Women. She was resentenced to life in 1972 when in that year, the death penalty was ruled unconstitutional. Inmate Krenwinkel was received with a death sentence at CIW on April 28, 1971. She was resentenced to life in 1972 as well.
They have both been at CIW continuously since then.
Van Houten was sentenced to death in 1971; however her original 1971 conviction and death sentence were reversed on appeal. She was retried in 1976. The jury could not reach a verdict. She was released on bail from Dec. 27, 1977 to July 5, 1978. She was convicted in her 1978 trial and sentenced to life in prison.
Since Atkins was received at CIW five days before Krenwinkel, she is the longest serving female inmate. Of all women currently in prison, no woman has been in prison longer than Atkins.