Robert Allerton Park, which belongs to the University of Illinois at Urbana–Champaign and includes 1,500 acres of woodland and prairie areas, a meadow, a conference and retreat center, formal sculpture gardens, hiking trails, lodging facilities, a summer camp location, and a Georgian style mansion, is located just outside Monticello, to the southwest.

The Monticello Railway Museum is a non-profit operating railroad that offers train rides to the public from May to October.

[8] Hayworth came to the area in 1822 to serve as a U.S. liaison agent to local Native American tribes.

Upon McReynolds' suggestion, the town was christened Monticello – after the home of Thomas Jefferson.

[9] The first house in the new town was built by a Mr. Cass who used the building as his home and a grocery store.

At the time, Monticello was part of Macon County, whose seat is in Decatur, nearly 30 miles away.

The government of the new county began conducting business on April 5, 1841 in the "Old Fort."

The Pepsin Syrup Company was founded in 1893, and became the leading employer in the city for decades until its closure in 1985.

In 1987 the 150th birthday of the town was celebrated with an open air reenactment and other festivities.

In a 2012 episode of the Comedy Central program The Daily Show, host Jon Stewart used the town in a joke segment, referring to it as Dogshit Bluffs.

29.7% of all households were made up of individuals, and 16.6% had someone living alone who was 65 years of age or older.