Hennepin's location on the
Illinois River, along with its proximity to a
Class I railroad (
Norfolk Southern Railway), and multiple inter and intrastate highway routes (
Interstate 80,
Interstate 39,
Illinois Route 180,
Illinois Route 89,
Illinois Route 71,
Illinois Route 26, and
Illinois Route 6) has, historically, made it a transportation hub attracting a variety of both small businesses and large industries. J&L Steel, a cold roll steel mill built by
Jones and Laughlin Steel Company on Hennepin's northern boundary, began operations in 1967 and employed 600 workers at height of production. The mill was later acquired by
Ling-Temco-Vought, at which time it became known as LTV Steel.
Ling-Temco-Vought's bankruptcy led to acquisition of the mill by
International Steel Group (ISG). As a result of additional acquisitions followed by a merger,
Putnam County's largest employer was absorbed by
ArcelorMittal. Long and arduous union lobbying and protests ultimately proved futile and
ArcelorMittal ceased production at the mill in March 2009. The mill's equipment was dismantled, sold, or shipped and on June 22, 2017, the vast plant was imploded. As of 2020, the 800 acres once occupied by the steel mill remain mostly vacant, though infrastructure has been retained in anticipation that another industry might one day purchase and redevelop the property. Hennepin Power Station, a coal-fired power plant near
Donnelley Wildlife Area on the western edge of town, was retired November 1, 2019. There are also
Cargill,
ADM, and CGB elevators throughout the area. Marquis Energy opened a 100 million gallon/year ICM/Fagen
ethanol plant just north of town in April 2008. ==Landmarks==