Waupun, WI has a population of 11,337 and is the 3,574th largest city in the United States. The population density is 2,452 per sq mi which is 2704% higher than the Wisconsin average and 2606% higher than the national average. The median age in Waupun is 38 which is approximately 4% lower than the Wisconsin average of 39. In Waupun, 53% of the population over 15 years of age are married, 94% speak English and 4% speak Spanish. 80% of Waupun residents were born in Wisconsin, 18% were born out of state, 0% were born outside of the United States and 2% were foreign born.