Income Inequality in San Mateo County, CA was 18.06593 Ratio in January of 2022, according to the United States Federal Reserve. Historically, Income Inequality in San Mateo County, CA reached a record high of 18.06593 in January of 2022 and a record low of 14.16146 in January of 2010. Trading Economics provides the current actual value, an historical data chart and related indicators for Income Inequality in San Mateo County, CA - last updated from the United States Federal Reserve on May of 2024.