Twin Groves Wind Farm is a wind farm in the U.S. state of Illinois, near the villages of Arrowsmith, Saybrook, and Ellsworth in McLean County. It consists of 240 operating wind turbines. Each wind turbine stands 280 ft (80 m) tall and has three 120-foot-long (39 m) blades. The wind farm was constructed from 2007 to February 2008. Twin Groves was the largest utility-scale wind farm east of the Mississippi River upon completion.