Fontana-on-Geneva Lake, WI has a population of 1,636 and is the 12,200th largest city in the United States. The population density is 487 per sq mi which is 457% higher than the Wisconsin average and 437% higher than the national average. The median age in Fontana-on-Geneva Lake is 57 which is approximately 46% higher than the Wisconsin average of 39. In Fontana-on-Geneva Lake, 69% of the population over 15 years of age are married, 97% speak English and 1% speak Spanish. 31% of Fontana-on-Geneva Lake residents were born in Wisconsin, 66% were born out of state, 1% were born outside of the United States and 1% were foreign born.