Our mission is to protect life,
property, and preserve the public peace

San Mateo County Sheriff's Office - A Tradition of Service Since 1856

About Us

The first Sheriff of San Mateo County took office in 1856 when the County was incorporated from parts of San Francisco and Santa Cruz Counties. As the chief law enforcement officer, the Sheriff is responsible for planning, organizing, directing, and reviewing the activities and operations of the Sheriff’s Office, including adult correctional facilities, rehabilitation, and re-entry services for offenders; public safety and emergency services; forensic laboratory services and specialized programs, such as narcotics, search and rescue, and bomb detection and disposal. The Sheriff and his Office coordinate assigned activities with other County departments and outside agencies, as well, and provide highly responsible and complex administrative support to the County Manager and Board of Supervisors.

Founded in 1856, the County of San Mateo, with the San Francisco Bay and Pacific Ocean making up the eastern and western most boundaries, covers over 500 square miles consisting of densely populated cities and rural farmland. Over 90% of the county’s 720,000 citizens reside in 20 incorporated cities.

Today, the Sheriff’s Office has over 800 sworn and civilian personnel who provide various law enforcement services to all cities in the County, including contract police services for the Peninsula Corridor Joint Powers Board (Caltrain), the San Mateo County Transit District (SamTrans), the City of San Carlos, Eichler Highlands and the towns of Woodside and Portola Valley. The Sheriff also provides investigative services to the San Francisco International Airport.

The SAN MATEO COUNTY SHERIFF'S OFFICE MISSION is to:

  • Protect life and property and preserve the public peace.
  • Enforce state laws and County ordinances.
  • Prevent crime.
  • Support positive youth development.
  • Apprehend criminals and supervise and care for incarcerated prisoners.
  • Coordinate emergency services.
  • Process civil actions.
  • Provide security for the Courts, Health Services, County employees, SamTrans/Caltrain, and the public visiting the County facilities.

To review the Policy Manual, which provides the operating guidelines for the San Mateo County Sheriff's Office, please click here.

Office History

  • 1856

    San Mateo County Sheriff's Office

    The San Mateo County Sheriff’s Office was founded in 1856.

  • 1857-1858

    Sheriff John W. Ackerson

    John W. Ackerson was elected as the first Sheriff of San Mateo County. Before being elected Sheriff, John Ackerson had previously worked for a lumber company. Sheriff Ackerson served for two years. After leaving the Sheriff's Office he went on to Puget Sound, Washington where he found much success in the logging and lumber industry.

  • 1857

    San Mateo Courthouse

    The first San Mateo County courthouse and jail was J.V. Diller's warehouse located on Redwood Creek. In 1858 a new courthouse and jail was built and were located on Broadway Avenue in Redwood City.

  • 1859

    Sheriff Silas Hovius

    Silas Hovius was elected as the second Sheriff of San Mateo County and served for two years. Prior to being Sheriff, he was a farmer on the coast.

  • 1865

    Sheriff Thomas W. Lathrop

    Thomas W. Lathrop was elected Sheriff and was a first Lieutenant of the Jefferson Cavalry, a local militia. There were concerns that the Confederate army would march through San Mateo County on their way to the San Francisco Mint. Their intent was to stop the flow of gold to the Union. Luckily, the Confederate army was stopped 80 miles from the California border.

  • 1930s

    Sheriff James McGrath

    In the 1930's, Sheriff James McGrath established a precedent by putting his only night patrol deputy in uniform. Deputy John O'Brien reported for duty wearing a khaki shirt, olive drab trousers, a police cap and a black leather coat with a gold badge. McGrath stayed in office for four terms, the longest tenure in San Mateo County Sheriff’s history.

  • 1951

    Modern Law Enforcement with Sheriff Earl B. Whitmore

    Modern Law Enforcement with Sheriff Whitmore In 1951, Earl B. Whitmore was elected Sheriff and brought modern policing standards to the Sheriff's Office. At the age of 34, Sheriff Whitmore was the youngest Sheriff in the United States. Prior to 1951, the Sheriff was the only person of rank within the office. Sheriff Whitmore established a new rank system consisting of a Chief Deputy Sheriff, Chief Civil Deputy, Chief Jailer, Captain of the Criminal Division, Lieutenant in charge of the Juvenile Division, Supervisor of Records and Identification Bureau, six Inspectors and four Patrol Sergeants.

  • 1953

    Sub-stations at Mills Field

    The Sheriff's Office increased in size from 54 to 91 employees. Sheriff Whitmore opened sub-stations at Mills Field (San Francisco Airport), Half Moon Bay, Sharp Park (Pacifica) and Brisbane to provide greater law enforcement coverage throughout the county. The first resident deputy was in Pescadero, which was the center of the south coast area, approximately 200 square miles. Sheriff Whitmore established standardization of police radios in all patrol cars.

  • 1951-1973

    Crash Wagons

    One of the most unique innovations was the “Crash Wagon.” Five ambulances were outfitted with police protection, investigation and rescue equipment. Staffed with a Deputy Sheriff and an Ambulance driver, these vehicles patrolled the county on a 24/7 basis and were able to respond to any incident. Sheriff Whitmore received national recognition, including United-International News Reels' 1954 film “Crash Wagons.” The film was distributed throughout the United States including 37 foreign countries. A letter from J. Edgar Hoover the first Director of the Federal Bureau of Investigation of the United States commending Sheriff Whitmore, was included in the film.

  • 1951-1973

    Crime Lab

    Sheriff Whitmore established a Crime Lab equipped with the latest and finest equipment for detection and examination of evidence. The services of the County Crime Lab were made available to all other agencies in San Mateo County.

  • 1951-1973

    Narcotics

    San Mateo County was one of the first in the state to train deputies in the field of narcotics, working with local law enforcement apprehending “dope peddlers and users.” Sheriff Whitmore assigned four deputies to attend service groups and other organizations in the county giving talks on narcotics and to acquaint the general public with the “devil's weed.” It later evolved into the Bureau of Special Services, which investigated vice, narcotics, gambling and the growing juvenile delinquency problem.

  • 1951-1973

    Work Furlough Program

    In 1966 the Sheriff’s Work Furlough Program was the first of it's kind in the United States, housing 110 inmates. Inmates that are convicted of minor crimes and employed could apply to this program. The program allowed individuals to attend work during the day and were able to stay at the correctional facility each night to serve out their sentencing. They paid for their own incarceration, saving the taxpayers thousands of dollars each year. The deputies at Work Furlough were trained in rehabilitation counseling and each was assigned 12 inmates for individual and group counseling.

  • 1973

    Sheriff Whitmore Retires

    Sheriff Whitmore Retires: In 1973, after 22 years as Sheriff Earl Whitmore retired.

  • 1973-1983

    Sheriff John R. McDonald

    Following Sheriff Whitmore’s retirement, the Board of Supervisors appointed John R. McDonald who was Chief of Police for the City of Redwood City to complete the duration of Sheriff Whitmore’s term. Sheriff McDonald went on to serve as Sheriff of San Mateo County for 10 years until he retired in 1983.

  • 1983

    Special Election

    Because Sheriff McDonald retired before the end of his term, the County held a special election to fill the vacancy. Lieutenant Brendan Maguire, along with several other lieutenants and captains in the Sheriff's Office, ran for Sheriff. Brendan Maguire won the election and became Sheriff in 1983.

  • 1986-1993

    Sheriff Brendan Maguire

    Sheriff Maguire ran again as the incumbent in the 1986 general election. The only other candidate was a man named Jim White, who had no prior association with the Sheriff’s Office. Two months before the election, Sheriff Maguire passed away. All members of the Sheriff's Office pulled together and campaigned for Sheriff Maguire. He was re-elected posthumously and Undersheriff Leonard Cardoza was appointed as Sheriff until a special election could be held. Several captains and lieutenants ran for Sheriff in a special election, and Leonard Cardoza was elected and continued as Sheriff until he retired in 1993.

  • 1993-2007

    Sheriff Don Horsley

    In 1993, Don Horsley was elected Sheriff of San Mateo County. Sheriff Horsley started his law enforcement career with the Pacifica Police Department and joined the Sheriff’s Office in 1972. He started his county career with the Sheriff’s Office as a Patrol Deputy in the City of East Palo Alto. Horsley served as Sheriff for 14 years retiring in 2007. After retiring, Sheriff Horsley was elected as Board President for the Sequoia Healthcare District. In 2010, he continued his career in public service by being elected to the San Mateo County Board of Supervisors.

  • 2007-2017

    Sheriff Greg Munks

    Greg Munks, who served as Undersheriff to Don Horsley for 14 years, ran unopposed in the election shortly following Sheriff Horsley's retirement. Sheriff Munks was re-elected in 2010. In 2014 he was re-elected for his third term as Sheriff. In 2016, Sheriff Munks retired before the end of his third term. During his tenure as Sheriff, Munks successfully opened the new Maple Street Correctional Center. The Maple Street Correctional Center earned its LEED certification for its environmentally conscious design. This new correctional center aids the Sheriff’s Office in reducing recidivism with effective jail programs.

  • 2017

    Sheriff Carlos G. Bolanos

    Following Sheriff Munks’ retirement, the Board of Supervisors appointed Undersheriff Carlos G. Bolanos as Sheriff. Sheriff Bolanos served as Undersheriff to Greg Munks for 10 years. As Undersheriff, Sheriff Bolanos was responsible for the day-to-day operations of the Sheriff’s Office, which included oversight of the Crime Lab, Technology Services, and Administration & Finance. He will continue to serve as Sheriff until the general election in 2018.

  • 2023

    Sheriff Christina Corpus

    The history of the San Mateo County Sheriff's Office has seen a significant milestone with the election of Sheriff Christina Corpus in June 2022. Sheriff Corpus began her journey in law enforcement in 2002, joining the San Mateo County Sheriff's Office as a Correctional Officer. Demonstrating her dedication and capabilities, she steadily climbed the ranks within the organization. Through her hard work and commitment, Corpus was promoted to the positions of Deputy Sheriff, Sergeant, and Lieutenant.

    Continuing her upward trajectory, Corpus reached the rank of Captain, where she assumed the important role of Millbrae Police Chief. This experience allowed her to gain valuable leadership skills and further strengthen her understanding of law enforcement operations.

    The people of San Mateo County recognized Corpus' outstanding contributions and she was sworn in as the 26th Sheriff of San Mateo County in January 2023. This election marked a momentous occasion, as Sheriff Corpus became the first female elected Sheriff in the history of San Mateo County. Additionally, she achieved another groundbreaking milestone by becoming the first Latina elected Sheriff in the entire state of California. Sheriff Christina Corpus's journey exemplifies perseverance, dedication, and a commitment to serving her community.