Historical Background

The History of Hennepin dates back to 1817 when a trading house was built by Beaubien, a Frenchman employed by the American Fur Company, a mile north of the current village. Around that time an independent trading post was built near there by Thomas Hartzell. This was called the Priarie de Prue. The Village of Hennepin was named in memory of Father Hennepin and his early exploration of the Illinois River.

The Village was surveyed by order of the County Commissioners in August and September of 1831. The original village limits included 12 blocks and an additional 8 were ordered to be surveyed shortly after. The first house in Hennepin was also constructed in 1831. During the Black Hawk war Hennepin served as the headquarters for the Putnam County Rangers. Hennepin grew slowly to a population of about 250 in 1836.

Hennepin was incorporated on February 13, 1837 with Jos. J. Holt serving as the first President of the Board of Trustees and Hugh N. Schooler as the Clerk. The citizens of Hennepin were very excited in 1856 about the prospect of a railroad from Bureau Junction to Fort Wayne, Indiana which would cross the Illinois River at Hennepin. However, this project and the Illinois River Railroad in 1853 never came to realization. The population of Hennepin in 1857 had grown to 711. The Village had a boon of growth to a population of 1,713 in 1860 and 2,144 in 1870. Due to the fact that the railroad never came to Hennepin, the population dwindled and the once thriving center of commerce dropped to a town of only 300 people in 1939.

Putnam County Courthouse in Hennepin

The Putnam County Courthouse is the oldest Illinois County Courthouse still in use. Built in 1839, the Greek Revival temple is complete with a white columned portico and is listed on the National Registry of Historic Places.

In 1936 the construction process for the bridge that crosses the Illinois River on Route 71 had begun. The construction of the bridge was completed and dedicated in 1939. The bridge eliminated the need for the ferry which for more than 100 years was the only way to cross the river. There have been additions over the years to the original structure. The bridge closed to automotive traffic in 1989. The demolition of the bridge began in late 2000.


In 1953 Illinois Power built a plant about a mile east of the Village along the Illinois River. In the late 1950's the plant produced 250 megawatts. In the 90's the plant was still able to supply the Village with the power they needed.

In 1965 with a village population of 391 Jones and Laughlin built a steel plant on 400 acres east of Hennepin. There were predictions that the plant would bring 15,000 jobs to the area. In the beginning about 110 were employed. In 1995 they employed 700 people. The construction of the steel plant also brought the construction of Interstate 180 that connects to Interstate 80 about 10 miles north of Hennepin.


The construction of this plant was supposed to bring a big growth to Putnam County. It was estimated that if all of the 6,500 acres they owned would be developed that the population would skyrocket to 65,000 by 1985. Hennepin’s population was to increase to 7,556 by 1985. This mass development did not come to fruition as projected. The population of the county only increased 12.9% from 1950 to 1990 while the population of Hennepin increased 114% in that same time period. In response to the growth that was to happen the city annexed a large amount of property for residential development east of Route 26. Most of this land is now used for farming.

In 1978 Exolon ESK built a plant on 100 acres just east of the steel mill along the Illinois River. The plant employs about 90 people. Exolon ships their product out by truck and rail.