[5] The city's name commemorates the Battle of Marengo, where Napoleon defeated the Austrian army.

[6] The Iowa County Courthouse, built in 1893, is on the National Register of Historic Places.

In 1859, abolitionist John Brown led a group of escaped slaves from Missouri to Michigan.

On February 20, the group stayed at the Draper B. Reynolds Farm 1.5 miles south of Marengo.

34.4% of all households were made up of individuals, and 17.2% had someone living alone who was 65 years of age or older.

Marengo is believed to be the smallest town in the United States to have received a donation from Andrew Carnegie for the construction of a library.

The Iowa County Historical Society operates the Pioneer Heritage Museum, located at 675 East South St., Marengo.

The museum houses two log cabins and a farmhouse, relocated from other sites in the area; and displays of farm implements, household artifacts, clothing and military history items from local residents.

The traditional yard game (known as krulbollen in Belgium) was brought to the area by Belgian immigrants in the late 19th and early 20th centuries.

[15] It is played by many local residents as well as by people in the neighboring towns of Victor, Clutier, Belle Plaine, Ladora, and Blairstown.

The Iowa Valley Tigers were the dominant 1985 State Champions in Track and Field for Class 2A, winning 45 points over the second place team's 31.50.

[16] This included Matt Zuber's Class 2A records in the long jump (24'-3") and the 110 meter high hurdles (14.1 sec).