Columbia, IL has a population of 10,193 and is the 3,891st largest city in the United States. The population density is 994 per sq mi which is 347% higher than the Illinois average and 998% higher than the national average. The median age in Columbia is 41 which is approximately 9% higher than the Illinois average of 37. In Columbia, 66% of the population over 15 years of age are married, 96% speak English and 1% speak Spanish. 54% of Columbia residents were born in Illinois, 44% were born out of state, 0% were born outside of the United States and 2% were foreign born.