Caltrans Districts

The District boundary definitions are primarily based on the California county boundaries. The Board of Equalization (BOE) County and City Boundary web service is the authoritative source of County boundaries and this was used to digitize the district boundaries based on the data from March 2023. This data is solely for informational purposes. District 9 has been operating independent of the Central Region since November 1, 2015. Kern County remains the only split county in the state, between Districts 6 and 9 respectively. The BOE data was also used to create the district boundary layers along the coastline.