The Wealth Index is based on a number of indicators of affluence including average household income and average net worth, but it also includes the value of material possessions and resources. It represents the wealth of the area relative to the national level. Values above or below 100 represent above-average wealth or below-average wealth compared to the national level.
| County | Wealth Index | |
|---|---|---|
| 1. | Marin County | 251 |
| 2. | San Mateo County | 224 |
| 3. | Santa Clara County | 203 |
| 4. | Contra Costa County | 189 |
| 5. | Alameda County | 167 |
| 6. | El Dorado County | 165 |
| 7. | Santa Cruz County | 158 |
| 8. | Placer County | 157 |
| 9. | Napa County | 156 |
| 10. | San Francisco County | 155 |
| 11. | Orange County | 151 |
| 12. | Ventura County | 142 |
| 13. | Sonoma County | 139 |
| 14. | Nevada County | 139 |
| 15. | Santa Barbara County | 136 |
| 16. | Solano County | 131 |
| 17. | San Luis Obispo County | 130 |
| 18. | San Diego County | 124 |
| 19. | Monterey County | 120 |
| 20. | San Benito County | 111 |
