Trinity County Profile Our Land Land area: 3179 sq. mi.Water area: 28.9 sq. mi.Population density: 4 people per square mile Cost of Living Mar. 2012 cost of living index in Trinity County: 92.7 (less than average, U.S. average is 100) Demographics Median resident age: 49.0 yearsCalifornia median age: 35.0 yearsMales: 7,113 (48.2%)Females: 6,673 (51.8%) Transportation Trinity Transit Airports Type of Workers Private wage or salary: 58%Government: 28%Self-employed, not incorporated: 15%Unpaid family work: 0%