Lannon, WI has a population of 1,053 and is the 14,835th largest city in the United States. The population density is 426 per sq mi which is 387% higher than the Wisconsin average and 370% higher than the national average. The median age in Lannon is 46 which is approximately 19% higher than the Wisconsin average of 39. In Lannon, 53% of the population over 15 years of age are married, 91% speak English and 7% speak Spanish. 82% of Lannon residents were born in Wisconsin, 14% were born out of state, 2% were born outside of the United States and 2% were foreign born.