Naperville is located in northeastern Illinois, straddling the border of DuPage and Will counties. It sits roughly 28 miles west of downtown Chicago, placing it comfortably within the Chicago metropolitan area. The city covers an area of approximately 39 square miles, the vast majority of which is land.
The defining geographic feature of Naperville is the DuPage River, specifically the West Branch and the East Branch, which flow through the city and converge just to the south. The river heavily influences the city's layout, providing a natural greenway that cuts through both residential and commercial zones. The region is characterized by typical Midwestern deciduous forests, though much of the original prairie and woodland has been developed into suburban landscapes, parks, and forest preserves.
Natural resources in the area historically included timber, waterways for early milling, and exceptionally fertile soil. Today, the area's "natural resources" are primarily its well-maintained green spaces, such as the Springbrook Prairie Forest Preserve, which offers hundreds of acres of protected wetlands, prairies, and forests.