Wauwatosa, WI has a population of 47,388 and is the 873rd largest city in the United States. The population density is 3,580 per sq mi which is 3995% higher than the Wisconsin average and 3852% higher than the national average. The median age in Wauwatosa is 38 which is approximately 3% lower than the Wisconsin average of 39. In Wauwatosa, 60% of the population over 15 years of age are married, 92% speak English and 3% speak Spanish. 71% of Wauwatosa residents were born in Wisconsin, 23% were born out of state, 1% were born outside of the United States and 5% were foreign born.