Olathe, CO has a population of 1,878 and is the 11,396th largest city in the United States. The population density is 1,294 per sq mi which is 2500% higher than the Colorado average and 1329% higher than the national average. The median age in Olathe is 31 which is approximately 15% lower than the Colorado average of 36. In Olathe, 51% of the population over 15 years of age are married, 57% speak English and 42% speak Spanish. 53% of Olathe residents were born in Colorado, 26% were born out of state, 0% were born outside of the United States and 21% were foreign born.