What is redistricting?

Every ten years, districts must be redrawn so that each supervisorial district is substantially equal in population. This process, called redistricting, is important in ensuring that each member of the board of supervisors represents about the same number of constituents. In Alameda County, the Board of Supervisors is responsible for drawing supervisorial districts. Redistricting is done using U.S. Census data, which is usually released to the states around March 31 of the year following the Decennial Census. Because of COVID-19 in 2020, the time period for conducting the Decennial Census was extended to October 15, 2020, resulting in a later delivery date of the final 2020 census data. For the County of Alameda, the redistricting process must be completed by December 15, 2021.

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Why does redistricting matter to me?

We have the privilege and right to elect our representatives. As the County’s population changes, the supervisorial boundaries must be adjusted to account for increases, decreases, and shifts in population and demographics to ensure that voters in each supervisorial district have an equal voice in electing their representatives. The elected representatives are responsible for public policy and funding decisions that impact the lives of County residents, such as law enforcement, hospitals, public works, children and family services and public social services, to name a few. The Board of Supervisors will seek input in adopting the next district map for our supervisorial districts. You have an opportunity to share with the Board of Supervisors how you think district boundaries should be drawn to best represent your community.

For more information you can contact staff at redistricting@acgov.org to find out more about the process.

What do the existing supervisorial districts look like?

You can find a map of the County’s current supervisorial districts here: Current Supervisorial Map

What criteria will our Board of Supervisors use when drawing district lines?

All electoral districts must comply with the United States Constitution, the California Constitution, and the federal Voting Rights Act of 1965 (52 U.S.C. Sec. 10301 et seq.).

California’s Elections Code Sec. 21500 provides a list of additional criteria the county must use, in the following order:


  1. Maintain Contiguity: Supervisorial districts shall be geographically contiguous. Contiguity means that a district must be connected, i.e. it can not be in multiple pieces. The Code specifies that areas that meet only at the points of adjoining corners are not contiguous.
  2. Keep Neighborhoods and Communities of Interest intact: The geographic integrity of any local neighborhood or local community of interest shall be respected in a manner that minimizes its division. A “community of interest” is a population that shares common social or economic interests that should be included within a single supervisorial district for purposes of its effective and fair representation. Communities of interest do not include relationships with political parties, incumbents, or political candidates.
  3. Keep Cities and Census Designated Places intact: The geographic integrity of a city or census designated place shall be respected in a manner that minimizes its division.
  4. Draw lines that people can understand: Supervisorial district boundaries should be easily identifiable and understandable by residents. If possible, use natural and artificial barriers, streets, or the boundaries of the county.
  5. Compactness: Where it does not conflict with the higher ranked criteria, districts shall be drawn so that nearby areas of population are not bypassed in favor of more distant populations. This is known as geographical compactness.
  6. The board shall not adopt supervisorial district boundaries for the purpose of favoring or discriminating against a political party.

How will the County notify the public about redistricting?

The County has created this accessible website that will feature redistricting information including handouts, meeting dates, times and locations, videos from previous meetings and much more. Please bookmark this website and check back frequently for updates.

The County is also using existing mailing lists to let residents know about the redistricting process and we encourage you to share information with your neighbors. We will also have a presence on social media in addition to reaching out to local media to help us publicize the redistricting process. In addition, County staff will reach out to local media to publicize the redistricting process. County staff will make a good faith effort to notify community groups of various kinds about the redistricting process.

Our public hearings and workshops will be available in applicable languages (live translations) if residents submit a request at least 72 hours (or 48 hours in some instances) in advance of the hearing or workshop. County staff will notify the public about redistricting hearings and workshops at least either 3 or 5 days prior to the hearing or workshop, post maps online before adoption, and create and maintain a dedicated web page for all relevant information about the redistricting process.

How can I get involved?

Residents and community groups are encouraged to participate in the redistricting public process, including attending workshops, hearings and public meetings, actively engaging by public comment (in person or in writing), and submitting draft maps.

The Board of Supervisors and County staff will be holding hearings and workshops to receive public input on where district lines should be drawn. Those hearings and workshops will be determined and posted on the Meetings page.

How do I sign up to get updates on redistricting?

To be added to the distribution list for redistricting information, sign up here.

Where can I submit comments?

Visit the Contact Us page so you can conveniently submit your comments online.

Comments can also be submitted by:

  • Email at redistricting@acgov.org
  • Telephone (510.670.5333)
  • Written correspondence. Address to 224 W. Winton Ave., Rm 110, Hayward, CA 94544 throughout this redistricting process.

Where can I submit suggested draft maps?

The County is providing a free, web-based mapping tool/application so that individuals and community groups can prepare and submit draft district map(s). The County will make this tool available in September of 2021, after the official redistricting database for the state has been released July 2021. Draft maps can be submitted through the tool or, if you are using different mapping software, by emailing a shapefile or equivalency file to (insert email here). You can also print a map and mail it or bring it to a redistricting workshop or hearing.

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