DeForest, WI has a population of 9,468 and is the 4,105th largest city in the United States. The population density is 1,264 per sq mi which is 1346% higher than the Wisconsin average and 1295% higher than the national average. The median age in DeForest is 35 which is approximately 9% lower than the Wisconsin average of 39. In DeForest, 64% of the population over 15 years of age are married, 95% speak English and 3% speak Spanish. 79% of DeForest residents were born in Wisconsin, 17% were born out of state, 1% were born outside of the United States and 3% were foreign born.