Pittsburg, KS has a population of 20,399 and is the 2,126th largest city in the United States. The population density is 1,561 per sq mi which is 4349% higher than the Kansas average and 1623% higher than the national average. The median age in Pittsburg is 26 which is approximately 29% lower than the Kansas average of 36. In Pittsburg, 40% of the population over 15 years of age are married, 91% speak English and 4% speak Spanish. 58% of Pittsburg residents were born in Kansas, 34% were born out of state, 1% were born outside of the United States and 7% were foreign born.