Redistricting & Reapportionment

Legislative districts, school district trustee areas, and city council district boundaries are reviewed every 10 years following the Census. The boundaries of these districts in Yolo County changed as of 2021.

Background

Article I, Section 2 of the Constitution of the United States mandates a count (census) of people living in the United States every 10 years. The first census after the American Revolution was taken in 1790. The U.S. Census Bureau's primary purpose is to allocate (reapportion) the seats in the U.S. House of Representatives among the states based on each state's population.

The number of members of the House of Representatives is capped at 435, and each member must represent roughly the same number of residents. Due to population changes, California now has 52 Congressional districts, one fewer than before the 2020 census. Even when the number of seats has not changed, states determine the boundaries of their Congressional districts in a process called redistricting.

State Redistricting

As a result of population changes, the boundaries for the Congressional, State Senate, State Assembly, and Board of Equalization districts were modified.

The California Citizens Redistricting Commission is responsible for eliciting public input and determining the new boundaries. The 14-member Commission is made up of five Republicans, five Democrats, and 4 members not affiliated with either party. The Commission drew the lines with strict, nonpartisan rules designed to create districts of relatively equal population that will provide fair representation for all.

California voters adopted new congressional district boundaries with the passage of Proposition 50 in 2025. The new congressional district lines will be in effect until the California Citizens Redistricting Commission redraws the maps after the 2030 Census.

In Yolo County, the offices of U.S. Representative in Congress, State Assembly, and State Board of Equalization are up for election in 2026 and will appear on the ballot. The 3rd State Senate District seat is up for election in 2028.

Below is a list of districts in Yolo County, along with a description. The California Citizens Redistricting Commission has its final maps on its website. The maps of the Congressional Districts created in 2025 are available on the California Geospatial Portal.

State Assembly District 4

  • All of Yolo County
  • All of Napa, Lake, and Colusa Counties
  • Portion of Sonoma County

State Senate District 3

  • All of Yolo County
  • All of Napa and Solano Counties
  • Portions of Contra Costa, Sacramento, and Sonoma Counties

U.S. Congress District 4

  • Most of Yolo County (Winters, Woodland and most of Davis. Capay, Dunnigan, Esparto, Guinda, Knights Landing and Madison)
  • All of Colusa, Napa, Sutter and Yuba Counties
  • Portions of Lake, Placer, Sacramento and Sonoma Counties

U.S. Congress District 6

  • All of West Sacramento
  • Portions of Placer and Sacramento Counties

U.S. Congress District 8

  • Clarksburg and Portions of Davis
  • All of Solano County
  • Portions of Contra Costa, Sacramento and San Joaquin Counties

Board of Equalization District 1

  • All of Yolo County
  • 19 counties in eastern California from Siskiyou to a portion of San Bernardino

County Redistricting

Section 21500 of the California Elections Code requires the County Board of Supervisors to review and adjust the supervisorial districts to equalize population counts. The Yolo County Board of Supervisors formed the Yolo County Advisory Redistricting Commission (ARC) to assist them in updating the supervisorial maps. The ARC held six public meetings, received a significant amount of input from the public, and chose three maps to recommend to the Board of Supervisors. For more information about the process, go to the Yolo County Redistricting webpage.

The Board of Supervisors further conducted two public hearings and on November 23, 2021 adopted the final map.

Description of each Supervisorial District:

District Maps1st Supervisorial District

  • Most of City of West Sacramento
  • Clarksburg
  • Portion of Yolo Bypass Wildlife Area
  • Deep Water Ship Canal

2nd Supervisorial District

  • Portion of Davis
  • Winters
  • Unincorporated Winters
  • Unincorporated West Davis/West Plainfield/Yolo County Airport

3rd Supervisorial District

  • Northern Area of City of West Sacramento
  • Portion of City of Woodland
  • Unincorporated West Woodland/Monument Hills
  • Unincorporated East Woodland/Elkhorn

4th Supervisorial District

  • Portion of Davis
  • Unincorporated East Davis
  • El Macero
  • Portion of Yolo Bypass Wildlife Area

5th Supervisorial District

  • Portion of City of Woodland
  • Brooks
  • Capay
  • Dunnigan
  • Esparto
  • Guinda
  • Knights Landing
  • Madison
  • Rumsey
  • Yolo
  • Zamora

City and School Districts

The boundaries of cities and school districts do not change as a result of the Census. Rather, it is the "sub-districts" within those jurisdictions, such as city council districts and trustee areas, that are reviewed for changes in population.

The following cities and school districts reviewed their jurisdictions for population changes:

Resources and Links