Polonia, WI has a population of 528 and is the 19,219th largest city in the United States. The population density is 158 per sq mi which is 81% higher than the Wisconsin average and 74% higher than the national average. The median age in Polonia is 40 which is approximately 3% higher than the Wisconsin average of 39. In Polonia, 63% of the population over 15 years of age are married, 98% speak English and 2% speak Spanish. 92% of Polonia residents were born in Wisconsin, 3% were born out of state, 2% were born outside of the United States and 3% were foreign born.