Colusa, CA has a population of 5,935 and is the 5,793rd largest city in the United States. The population density is 3,236 per sq mi which is 1292% higher than the California average and 3471% higher than the national average. The median age in Colusa is 31 which is approximately 13% lower than the California average of 36. In Colusa, 52% of the population over 15 years of age are married, 58% speak English and 40% speak Spanish. 72% of Colusa residents were born in California, 8% were born out of state, 1% were born outside of the United States and 19% were foreign born.