Sterling is a city in Whiteside County, Illinois, United States. The population was 15,370 at the 2010 census, down from 15,451 at the 2000 census. Formerly nicknamed "The Hardware Capital of the World", Sterling has long been associated with manufacturing and the steel industry.
Sterling is located along the north bank of the Rock River opposite its twin city of Rock Falls. The terrain is mostly flat. The land immediately outside of town is almost entirely farmland. The prairie soil is part of one of the world's most fertile growing areas.
As of the census of 2000, there were 15,596 people, 6,234 households, and 3,946 families residing in the city. The population density was 3,307.0 people per square mile (1,277.4/km²). There were 6,596 housing units at an average density of 1,411.8 per square mile (545.3/km²). The racial makeup of the city was 84.36% White, 2.25% African American, 0.41% Native American, 0.81% Asian, 0.01% Pacific Islander, 9.82% from other races, and 2.35% from two or more races. Hispanic or Latino of any race were 19.24% of the population.