California State Prison, Sacramento (SAC) is a male-only state prison located in the city of Folsom, in Sacramento County, California. The facility is also referenced as Sacramento State Prison, CSP-Sacramento, CSP-SAC, and occasionally, New Folsom or New Folsom Prison which was its official name prior to October 1992.

Because the facility is adjacent to Folsom State Prison (FSP), both SAC and FSP share the mailing address: Represa, CA 95671. Represa (translated as "dam" from the Spanish language) is the name given to the State Prison post office because its adjacency to Folsom Dam.

The facility houses maximum security prisoners who were difficult to manage at other prisons and who have long sentences.

As of Fiscal Year 2006/2007, SAC had a total of 1,585 staff and an annual operating budget of $187 million. As of September 2007, it had a design capacity of 1,788 but a total institution population of 3,260, for an occupancy rate of 182.3 percent.

As of July 31, 2022, SAC was incarcerating people at 111.1% of its design capacity, with 2,031 occupants.

SAC's 1,200 acres (490 ha) facilities include:

The prison has "three similar but separate self-contained facilities... each comprised of eight housing blocks and a recreation yard." The housing blocks "are partitioned into three separate, self-contained sections forming a 180 degree half circle." The "180" design is considered the "most secure prison design" because it "gives control-booth officers a straight-on look at prisoners." In contrast, the "270" design "with portions of the house reaching back behind the blind side of the booth" is considered less secure.

When they were built, the maximum-security buildings of what is now SAC were considered an "addition" to FSP. The first FSP inmates were transferred to the addition on October 1, 1986. In 1986, the prison was administered by the Folsom warden and was called New Folsom. In October 1992, its name was changed to CSP-Sacramento, and was administered as a separate prison with its own warden."