Sterling. 1 City (1990 pop. 10,362), seat of Logan co., NE Colo., on the South Platte River; inc. 1884. It is the trading and shipping center of an agricultural area (grain, cattle, dairy products). Oil-related industries developed when oil was discovered nearby in the 1950s. Farm machinery and metal products are manufactured. 2 City (1990 pop. 15,132), Whiteside co., NW Ill., on the Rock River opposite Rock Falls; inc. 1841. It is an industrial center in a farm region. Steel products and machinery are manufactured.