Contra Costa County will see its highest tax assessment roll in its history in 2024-25, the county said Monday.

County tax assessor Gus S. Kramer on Friday signed and filed the official "2024-2025 Assessor's Close of Roll Affidavit."

An assessment roll is a public record containing information about individual pieces of land. Assessment rolls are used to determine property values and property taxes.

The increase to the local tax base for 2024-2025 is more than $11.16 billion.

The county said it represents a 4.17% increase in assessed value and brings the total net local assessment roll to more than $278.83 billion. 

Cities with the largest increases in assessed value include Antioch, Oakley, and Martinez with increases ranging from 4.99% up to 6.09%, the county said.

San Ramon, Concord, and Walnut Creek saw the lowest assessed value increases ranging from 2.97% down to 1.45%.  

The assessment roll now consists of 380,681 parcels, an increase of 1,239 over the previous year.

The assessor's annual letter to the Board of Supervisors and 2024-2025 Assessment Roll Reports can be found on the county's website.