The following lists members of the Board of Supervisors over the last 130+ years. Prior to 1889, the supervisorial districts were set up differently with the County represented by four districts and at large members when the County was founded in 1850. Bold names indicate the Supervisor served as Chair of the Board of Supervisors.
| Year | District 1 | District 2 | District 3 | District 4 | District 5 |
| 1889 | Buck, Joshua | Woolman, John H. | Gunn, Chester | Stice, Andrew J. | Woods, John M. |
| 1890 | Buck, Joshua | Woolman, John H. | Gunn, Chester | Stice, Andrew J. | Woods, John M. |
| 1891 | Buck, Joshua | Woolman, John H. | Gunn, Chester | Judson, John | Rainbow, James |
| 1892 | Buck, Joshua | Woolman, John H. | Gunn, Chester | Judson, John | Rainbow, James |
| 1893 | Nason, Arthur | Wetzell, Will W. | Jasper, James | Judson, John | Rainbow, James |
| 1894 | Nason, Arthur | Wetzell, Will W. | Jasper, James | Judson, John | Rainbow, James |
| 1895 | Nason, Arthur | Wetzell, Will W. | Jasper, James | Justice, William | Griffin, John |
| 1896 | Nason, Arthur | Wetzell, Will W. | Jasper, James | Justice, William | Griffin, John |
| 1897 | Nason, Arthur | Wetzell, Will W. | Jasper, James | Justice, William | Griffin, John |
| 1898 | Cherry, Howard | Swallow, Charles H. | Jasper, James | Justice, William | Griffin, John |
| 1899 | Cherry, Howard | Swallow, Charles H. | Jasper, James | Justice, William | Griffin, John |
| 1900 | Cherry, Howard | Swallow, Charles H. | Jasper, James | Justice, William | Griffin, John |
| 1901 | Cherry, Howard | Swallow, Charles H. | Jasper, James | Justice, William | Griffin, John |
| 1902 | Cherry, Howard | Swallow, Charles H. | Jasper, James | Justice, William | Griffin, John |
| 1903 | Cherry, Howard | Swallow, Charles H. | Jasper, James | Justice, William | Griffin, John |
| 1904 | Cherry, Howard | Swallow, Charles H. | Jasper, James | Justice, William | Griffin, John |
| 1905 | Cherry, Howard | Cassidy, James | Jasper, James | Justice, William | Griffin, John |
| 1906 | Cherry, Howard | Cassidy, James | Foster, Joseph | Justice, William | Griffin, John |
| 1907 | Cherry, Howard | Cassidy, James | Foster, Joseph | Webster, Frank S. | Griffin, John |
| 1908 | Adams, Daniel K. | Cassidy, James | Foster, Joseph | Fisher, Thomas | Griffin, John |
| 1909 | Adams, Daniel K. | Cassidy, James | Foster, Joseph | Fisher, Thomas | Griffin, John |
| 1910 | Adams, Daniel K. | Cassidy, James | Foster, Joseph | Fisher, Thomas | Griffin, John |
| 1911 | Smith, John | Cassidy, James | Foster, Joseph | Fisher, Thomas | Westfall, George |
| 1912 | Smith, John | Cassidy, James | Foster, Joseph | Fisher, Thomas | Westfall, George |
| 1913 | Smith, John | Swallow, Charles H. | Foster, Joseph | Fisher, Thomas | Westfall, George |
| 1914 | Smith, John | Swallow, Charles H. | Foster, Joseph | Fisher, Thomas | Westfall, George |
| 1915 | Smith, John | Swallow, Charles H. | Foster, Joseph | Good, Charles | Westfall, George |
| 1916 | Smith, John | Swallow, Charles H. | Foster, Joseph | Good, Charles | Westfall, George |
| 1917 | Greene, Harry P. | Swallow, Charles H. | Foster, Joseph | Good, Charles | Westfall, George |
| 1918 | Greene, Mildrid | Swallow, Charles H. | Foster, Joseph | Good, Charles | Westfall, George |
| 1919 | Greene, Mildrid | Hornbeck, Edward | Foster, Joseph | Good, Charles | Westfall, George |
| 1920 | Greene, Mildrid | Hornbeck, Edward | Foster, Joseph | Good, Charles | Westfall, George |
| 1921 | Greene, Mildrid | Hornbeck, Edward | Foster, Joseph | Good, Charles | Westfall, George |
| 1922 | Greene, Mildrid | Hornbeck, Edward | Foster, Joseph | Good, Charles | Westfall, George |
| 1923 | Greene, Mildrid | Hornbeck, Edward | Foster, Joseph | Good, Charles | Hurley, Tom |
| 1924 | Greene, Mildrid | Hornbeck, Edward | Foster, Joseph | Good, Charles | Hurley, Tom |
| 1925 | Greene, Mildrid | Hornbeck, Edward | Foster, Joseph | Good, Charles | Hurley, Tom |
| 1926 | Greene, Mildrid | Hornbeck, Edward | Foster, Joseph | Good, Charles | Hurley, Tom |
| 1927 | Greene, Mildrid | Hornbeck, Edward | Foster, Joseph | Good, Charles | Hurley, Tom |
| 1928 | Greene, Mildrid | Hornbeck, Edward | Foster, Joseph | Good, Charles | Hurley, Tom |
| 1929 | Hastings, Edgar | Hornbeck, Edward | Aul, LeRoy H. | Good, Charles | Hurley, Tom |
| 1930 | Hastings, Edgar | Hornbeck, Edward | Aul, LeRoy H. | Good, Charles | Hurley, Tom |
| 1931 | Hastings, Edgar | Hornbeck, Edward | Aul, LeRoy H. | McMullen, Stewart | Hurley, Tom |
| 1932 | Hastings, Edgar | Richards, LeRoy | Trussell, Ray | McMullen, Stewart | Hurley, Tom |
| 1933 | Hastings, Edgar | Richards, LeRoy | Trussell, Ray | McMullen, Stewart | Hurley, Tom |
| 1934 | Hastings, Edgar | Richards, LeRoy | Trussell, Ray | McMullen, Stewart | Hurley, Tom |
| 1935 | Hastings, Edgar | Richards, LeRoy | Trussell, Ray | Hicks, Harvey | Sweet, Bryan A. |
| 1936 | Hastings, Edgar | Richards, LeRoy | Trussell, Ray | Hicks, Harvey | Sweet, Bryan A. |
| 1937 | Bellon, Walter | Richards, LeRoy | Faddis, John | Hicks, Harvey | Sweet, Bryan A. |
| 1938 | Bellon, Walter | Richards, LeRoy | Faddis, John | Hicks, Harvey | Sweet, Bryan A. |
| 1939 | Bellon, Walter | Richards, LeRoy | Faddis, John | Warner, Harry | Hart, William T. |
| 1940 | Bellon, Walter | Richards, LeRoy | Faddis, John | Warner, Harry | Hart, William T. |
| 1941 | Bellon, Walter | Bird, David | Faddis, John | Warner, Harry | Howell, Dean |
| 1942 | Bellon, Walter | Bird, David | Faddis, John | Warner, Harry | Howell, Dean |
| 1943 | Bellon, Walter | Bird, David | Faddis, John | Warner, Harry | Howell, Dean |
| 1944 | Bellon, Walter | Bird, David | Faddis, John | Warner, Harry | Howell, Dean |
| 1945 | Rossi, Dan | Bird, David | Robbins, James | Austin, De Graff | Howell, Dean |
| 1946 | Rossi, Dan | Bird, David | Robbins, James | Austin, De Graff | Howell, Dean |
| 1947 | Rossi, Dan | Bird, David | Robbins, James | Austin, De Graff | Howell, Dean |
| 1948 | Rossi, Dan | Bird, David | Robbins, James | Austin, De Graff | Howell, Dean |
| 1949 | Rossi, Dan | Bird, David | Robbins, James | Austin, De Graff | Howell, Dean |
| 1950 | Rossi, Dan | Bird, David | Robbins, James | Austin, De Graff | Howell, Dean |
| 1951 | Gibson, Frank | Bird, David | Robbins, James | Austin, De Graff | Howell, Dean |
| 1952 | Gibson, Frank | Bird, David | Robbins, James | Austin, De Graff | Howell, Dean |
| 1953 | Gibson, Frank | Bird, David | Robbins, James | Austin, De Graff | Howell, Dean |
| 1954 | Gibson, Frank | Bird, David | Robbins, James | Austin, De Graff | Howell, Dean |
| 1955 | Gibson, Frank | Bird, David | Robbins, James | Austin, De Graff | Howell, Dean |
| 1956 | Gibson, Frank | Bird, David | Robbins, James | Austin, De Graff | Howell, Dean |
| 1957 | Gibson, Frank | Bird, David | Dent, Robert | Austin, De Graff | Howell, Dean |
| 1958 | Gibson, Frank | Bird, David | Dent, Robert | Austin, De Graff | Howell, Dean |
| 1959 | Gibson, Frank | Bird, David | Dent, Robert | Austin, De Graff | Howell, Dean |
| 1960 | Gibson, Frank | Bird, David | Dent, Robert | Austin, De Graff | Howell, Dean |
| 1961 | Gibson, Frank | Bird, David | Dent, Robert | Austin, De Graff | Cozens, Robert |
| 1962 | Gibson, Frank | Bird, David | Dent, Robert | Austin, De Graff | Cozens, Robert |
| 1963 | Gibson, Frank | Bird, David | Dent, Robert | Austin, De Graff | Cozens, Robert |
| 1964 | Gibson, Frank | Bird, David | Dent, Robert | Austin, De Graff | Cozens, Robert |
| 1965 | Gibson, Frank | Boney, Henry | Dent, Robert | Austin, De Graff | Cozens, Robert |
| 1966 | Gibson, Frank | Boney, Henry | Dent, Robert | Austin, De Graff | Cozens, Robert |
| 1967 | Gibson, Frank | Boney, Henry | Dent, Robert | Austin, De Graff | Cozens, Robert |
| 1968 | Gibson, Frank | Boney, Henry | Dent, Robert | Austin, De Graff | Cozens, Robert |
| 1969 | Walsh, Jack | Boney, Henry | Scheidle, Harry | Austin, De Graff | Cozens, Robert |
| 1970 | Walsh, Jack | Boney, Henry | Scheidle, Harry | Austin, De Graff | Craven, William |
| 1971 | Walsh, Jack | Boney, Henry | Scheidle, Harry | Bear, Jim | Craven, William |
| 1972 | Walsh, Jack | Boney, Henry | Scheidle, Harry | Bear, Jim | Craven, William |
| 1973 | Walsh, Jack | Brown, Dick | Conde, Lou | Bear, Jim | Craven, William |
| 1974 | Walsh, Jack | Brown, Dick | Conde, Lou | Bear, Jim | Taylor, Lee |
| 1975 | Walsh, Jack | Brown, Dick | Conde, Lou | Bear, Jim | Taylor, Lee |
| 1976 | Walsh, Jack | Brown, Dick | Conde, Lou | Bates, Jim | Taylor, Lee |
| 1977 | Hamilton, Tom | Moore, Lucille | Hedgecock, Roger | Bates, Jim | Taylor, Lee |
| 1978 | Hamilton, Tom | Moore, Lucille | Hedgecock, Roger | Bates, Jim | Taylor, Lee |
| 1979 | Hamilton, Tom | Moore, Lucille | Hedgecock, Roger | Bates, Jim | Eckert, Paul |
| 1980 | Hamilton, Tom | Moore, Lucille | Hedgecock, Roger | Bates, Jim | Eckert, Paul |
| 1981 | Hamilton, Tom | Fordem, Paul | Hedgecock, Roger | Bates, Jim | Eckert, Paul |
| 1982 | Hamilton, Tom | Fordem, Paul | Hedgecock, Roger | Bates, Jim | Eckert, Paul |
| 1983 | Hamilton, Tom | Fordem, Paul | Boarman, Patrick | Williams, Leon | Eckert, Paul |
| 1984 | Hamilton, Tom | Fordem, Paul | Boarman, Patrick | Williams, Leon | Eckert, Paul |
| 1985 | Bilbray, Brian | Bailey, George | Golding, Susan | Williams, Leon | Eckert, Paul |
| 1986 | Bilbray, Brian | Bailey, George | Golding, Susan | Williams, Leon | Eckert, Paul |
| 1987 | Bilbray, Brian | Bailey, George | Golding, Susan | Williams, Leon | MacDonald, John |
| 1988 | Bilbray, Brian | Bailey, George | Golding, Susan | Williams, Leon | MacDonald, John |
| 1989 | Bilbray, Brian | Bailey, George | Golding, Susan | Williams, Leon | MacDonald, John |
| 1990 | Bilbray, Brian | Bailey, George | Golding, Susan | Williams, Leon | MacDonald, John |
| 1991 | Bilbray, Brian | Bailey, George | Golding, Susan | Williams, Leon | MacDonald, John |
| 1992 | Bilbray, Brian | Bailey, George | Golding, Susan | Williams, Leon | MacDonald, John |
| 1993 | Bilbray, Brian | Jacob, Dianne | Slater-Price, Pam | Williams, Leon | MacDonald, John |
| 1994 | Bilbray, Brian | Jacob, Dianne | Slater-Price, Pam | Williams, Leon | MacDonald, John |
| 1995 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 1996 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 1997 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 1998 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 1999 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 2000 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 2001 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 2002 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 2003 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 2004 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 2005 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 2006 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 2007 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 2008 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 2009 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 2010 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 2011 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 2012 | Cox, Greg | Jacob, Dianne | Slater-Price, Pam | Roberts, Ron | Horn, Bill |
| 2013 | Cox, Greg | Jacob, Dianne | Roberts, Dave | Roberts, Ron | Horn, Bill |
| 2014 | Cox, Greg | Jacob, Dianne | Roberts, Dave | Roberts, Ron | Horn, Bill |
| 2015 | Cox, Greg | Jacob, Dianne | Roberts, Dave | Roberts, Ron | Horn, Bill |
| 2016 | Cox, Greg | Jacob, Dianne | Roberts, Dave | Roberts, Ron | Horn, Bill |
| 2017 | Cox, Greg | Jacob, Dianne | Gaspar, Kristin | Roberts, Ron | Horn, Bill |
| 2018 | Cox, Greg | Jacob, Dianne | Gaspar, Kristin | Roberts, Ron | Horn, Bill |
| 2019 | Cox, Greg | Jacob, Dianne | Gaspar, Kristin | Fletcher, Nathan | Desmond, Jim |
| 2020 | Cox, Greg | Jacob, Dianne | Gaspar, Kristin | Fletcher, Nathan | Desmond, Jim |
| 2021 | Vargas, Nora | Anderson, Joel | Lawson-Remer, Terra | Fletcher, Nathan | Desmond, Jim |
| 2022 | Vargas, Nora | Anderson, Joel | Lawson-Remer, Terra | Fletcher, Nathan | Desmond, Jim |
| 2023 | Vargas, Nora | Anderson, Joel | Lawson-Remer, Terra | Fletcher, Nathan* Montgomery Steppe, Monica | Desmond, Jim |
| 2024 | Vargas, Nora | Anderson, Joel | Lawson-Remer, Terra | Montgomery Steppe, Monica | Desmond, Jim |
| 2025 | Aguirre, Paloma** | Anderson, Joel | Lawson-Remer, Terra | Montgomery Steppe, Monica | Desmond, Jim |
*Nathan Fletcher resigned May 15, 2023. Monica Montgomery Steppe was elected to District 4 on November 7, 2023 and sworn in on December 5, 2023.
**Nora Vargas did not assume her second term on January 6, 2025. Paloma Aguirre was elected to District 1 on July 1, 2025 and sworn in on July 22, 2025.

