USP Atwater (high-security)

Male

Gender

High

Security Level

1,187 (September 2023)

Population (Nov. 2025)

United States Penitentiary, Atwater (USP Atwater) is a high-security federal prison for male inmates in Atwater, California. The site sits in Merced County, in the San Joaquin Valley, on land that was once part of Castle Air Force Base. The penitentiary opened in 2001. It is run by the Federal Bureau of Prisons. A minimum-security satellite camp shares the grounds and holds a separate, smaller inmate population. As of September 2023, the penitentiary held about 1,187 inmates.

Overview

USP Atwater is one of the federal system's high-security penitentiaries. It houses men who carry longer sentences, more serious disciplinary histories, or a need for closer supervision than a medium or low facility provides. The compound has a reinforced perimeter, controlled inmate movement, and separate housing for prisoners who cannot be kept in general population.

The mailing address is 1 Federal Way, Atwater, CA 95301. The adjoining camp operates at the minimum-security level. Camp inmates are typically nearing the end of their terms and live under far looser controls than the men inside the main penitentiary. The two facilities run as one institution under a single warden but keep their populations apart.

The site has a military past. Before the prison, the land belonged to Castle Air Force Base, which closed in the early 1990s. The penitentiary was built as part of a federal expansion of high-security capacity during that decade.

History

The Bureau of Prisons activated USP Atwater in 2001 and began taking inmates that year. It came online during a stretch when the federal government added several new high-security penitentiaries to keep pace with a rising prison population.

The institution has drawn attention for violence. On June 20, 2008, Correctional Officer Jose V. Rivera was stabbed to death inside a housing unit. Rivera was 22. He was trying to return two inmates, Joseph Cabrera Sablan and James Ninete Leon Guerrero, to their cell when Sablan attacked him with a homemade shank and Guerrero held him down. Rivera was stabbed more than twenty times. Both men were charged with the murder. Guerrero pleaded guilty in March 2014 and received life without parole. Sablan was sentenced to life without parole in September 2015 under a plea agreement that took the death penalty off the table. Rivera's death became a touchstone in debates over staffing and officer safety at federal penitentiaries.

Violence has not been confined to inmates and staff. In August 2006, inmate Juwan Ferguson beat his cellmate, Domosanies Slaughter, at the penitentiary. Slaughter died days later.

The facility has stayed in the news through later staffing and safety problems. The American Federation of Government Employees, the union representing federal correctional officers, has flagged drug-exposure incidents at federal prisons, including airborne and contact exposure to synthetic substances that put staff at risk. The union has cited those hazards in its push for better protections at institutions of this type.

Notable Inmates and Incidents

In November 2023, correctional officer Sandra Munagay assaulted an inmate at USP Atwater and then tried to hide it. She pleaded guilty in 2024 to federal charges of deprivation of rights under color of law and falsification of a record in a federal investigation. Court records showed she struck the inmate and then filed a false report to justify the force. The Department of Justice Office of the Inspector General investigated the case, and the U.S. Attorney's Office for the Eastern District of California prosecuted it.

The penitentiary has also figured in major gang prosecutions. The Aryan Brotherhood ran a racketeering operation that reached into California prisons, directing drug trafficking and murders through smuggled cellphones. Members were tried and sentenced over conduct tied to that conspiracy. In May 2025, the Eastern District of California secured life sentences against members convicted of racketeering and murder in aid of racketeering.

Several inmates serving long federal terms have been held at USP Atwater. Jerry Whitworth, convicted in the Walker spy ring espionage case, received a 365-year sentence and has been designated here. Khalid Ali-M Aldawsari, convicted of attempting to use a weapon of mass destruction, is serving a life sentence.

Location and Visitation

USP Atwater is at 1 Federal Way, Atwater, CA 95301, in Merced County.

Visiting a high-security penitentiary takes advance approval. The Bureau of Prisons requires each visitor to be placed on an inmate's approved visiting list, which involves a background check before the first visit. Visitors pass through search procedures on arrival. Visits take place in a controlled visiting room under staff supervision. Rules on dates, times, dress, and what visitors may bring are specific and can change. For full and current visiting information, check the institution's official page on the Bureau of Prisons website: Official BOP Page. See also our Visitation Guide.