Crestwood, MO has a population of 11,941 and is the 3,428th largest city in the United States. The population density is 3,318 per sq mi which is 3741% higher than the Missouri average and 3562% higher than the national average. The median age in Crestwood is 45 which is approximately 16% higher than the Missouri average of 38. In Crestwood, 63% of the population over 15 years of age are married, 93% speak English and 3% speak Spanish. 74% of Crestwood residents were born in Missouri, 20% were born out of state, 0% were born outside of the United States and 5% were foreign born.