Cassville, WI has a population of 942 and is the 15,498th largest city in the United States. The population density is 976 per sq mi which is 1016% higher than the Wisconsin average and 977% higher than the national average. The median age in Cassville is 49 which is approximately 26% higher than the Wisconsin average of 39. In Cassville, 61% of the population over 15 years of age are married, 99% speak English and 0% speak Spanish. 66% of Cassville residents were born in Wisconsin, 34% were born out of state, 0% were born outside of the United States and 0% were foreign born.