Sterling is a city in Whiteside County, Illinois, United States. The population was 14,782 at the 2020 census, down from 15,370 in 2010. Formerly nicknamed “Hardware Capital of the World”, the city has long been allied with manufacturing and the steel industry.

Sterling lies along the north bank of the Rock River, opposite its twin city, Rock Falls. The terrain is mostly flat. The land shortly outside of town is regarding entirely farmland. The prairie soil is part of one of the world’s most fruitful growing areas. According to the 2010 census, Sterling has a total Place of 5.943 square miles (15.39 km), of which 5.71 square miles (14.79 km²) (or 96.08%) is land and 0.233 square miles (0.60 km) (or 3.92%) is water.

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 inhabitants per square mile (1,276.8/km²). There were 6,596 housing units at an average density of 1,411.8 per square mile (545.1/km). 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 additional races, and 2.35% from two or more races. Hispanic or Latino of any race were 19.24% of the population.

There were 6,234 households, out of which 30.3% had children under the age of 18 living like them, 47.2% were married couples full of life together, 12.2% had a female householder next no husband present, and 36.7% were non-families. 31.4% of whatever households were made in the works of individuals, and 14.0% had someone successful alone who was 65 years of age or older. The average household size was 2.41 and the average relatives size was 3.04.