Oconomowoc, WI has a population of 16,289 and is the 2,625th largest city in the United States. The population density is 1,404 per sq mi which is 1506% higher than the Wisconsin average and 1450% higher than the national average. The median age in Oconomowoc is 39 which is approximately 1% lower than the Wisconsin average of 39. In Oconomowoc, 63% of the population over 15 years of age are married, 94% speak English and 4% speak Spanish. 72% of Oconomowoc residents were born in Wisconsin, 24% were born out of state, 1% were born outside of the United States and 4% were foreign born.