Stillwater, MN has a population of 19,142 and is the 2,274th largest city in the United States. The population density is 2,378 per sq mi which is 3743% higher than the Minnesota average and 2525% higher than the national average. The median age in Stillwater is 41 which is approximately 9% higher than the Minnesota average of 38. In Stillwater, 58% of the population over 15 years of age are married, 96% speak English and 1% speak Spanish. 68% of Stillwater residents were born in Minnesota, 27% were born out of state, 1% were born outside of the United States and 3% were foreign born.