Northfield is a village in Cook County, Illinois, United States, located approximately 19 miles (31 km) north of downtown Chicago. It is part of a collection of residential communities north of Chicago that belong to New Trier Township and the greater North Shore. As of the 2010 census, the village's population was 5,420.
Northfield is located in Northfield Township, Cook County at 42°6'N 87°46'W (42.10,-87.77). According to the 2010 census, Northfield has a total area of 3.21 square miles (8.31 km2), all land.
As of the census of 2000, there were 5,389 people, 2,155 households, and 1,532 families residing in the village. The population density was 1,822.4 people per square mile (702.9/km2). There were 2,241 housing units at an average density of 757.9 per square mile (292.3/km2). The racial makeup of the village was 92.48% White, 0.52% African American, 0.04% Native American, 5.57% Asian, 0.43% from other races, and 0.96% from two or more races. Hispanic or Latino of any race were 1.67% of the population.
There were 2,155 households, out of which 31.2% had children under the age of 18 living with them, 62.8% were married couples living together, 6.3% had a female householder with no husband present, and 28.9% were non-families. 26.1% of all households were made up of individuals, and 13.5% had someone living alone who was 65 years of age or older.