Wausau, WI has a population of 39,138 and is the 1,063rd largest city in the United States. The population density is 2,072 per sq mi which is 1819% higher than the Wisconsin average and 2187% higher than the national average. The median age in Wausau is 39 which is approximately equal to the Wisconsin average of 39. In Wausau, 53% of the population over 15 years of age are married, 85% speak English and 2% speak Spanish. 72% of Wausau residents were born in Wisconsin, 20% were born out of state, 1% were born outside of the United States and 7% were foreign born.