Northbrook, OH has a population of 10,297 and is the 3,865th largest city in the United States. The population density is 5,284 per sq mi which is 1952% higher than the Ohio average and 5732% higher than the national average. The median age in Northbrook is 34 which is approximately 13% lower than the Ohio average of 39. In Northbrook, 50% of the population over 15 years of age are married, 94% speak English and 3% speak Spanish. 75% of Northbrook residents were born in Ohio, 20% were born out of state, 0% were born outside of the United States and 5% were foreign born.