List of California Counties by Human Development Index

This list ranks all 58 counties in California by their Human Development Index, a composite measure of income, education, and life expectancy. The highest HDI counties are Marin, Santa Clara, San Mateo, and San Francisco, all in the Bay Area, reflecting the region's concentration of wealth, education, and health resources. At the other end, Tulare County, Imperial County, and Del Norte and Kern County rank lowest, representing largely rural and agricultural counties. Mono County is now included in the ranking with corrected data. Overall, the list highlights the HDI gap between urban coastal counties and rural inland regions..