Colfax, CA has a population of 2,189 and is the 10,506th largest city in the United States. The population density is 1,557 per sq mi which is 570% higher than the California average and 1618% higher than the national average. The median age in Colfax is 33 which is approximately 9% lower than the California average of 36. In Colfax, 51% of the population over 15 years of age are married, 95% speak English and 2% speak Spanish. 77% of Colfax residents were born in California, 21% were born out of state, 1% were born outside of the United States and 1% were foreign born.