Unemployment Rate in Sierra County, CA was 5.70% in December of 2025, according to the United States Federal Reserve. Historically, Unemployment Rate in Sierra County, CA reached a record high of 20.60 in February of 2010 and a record low of 3.00 in September of 2022. Trading Economics provides the current actual value, an historical data chart and related indicators for Unemployment Rate in Sierra County, CA - last updated from the United States Federal Reserve on April of 2026.