The population of Marengo is made up of many different races and sexes, and the percentage of those belonging to racial or ethnic groups is quite diverse. For instance, 34% of Marengo's residents claim to be White, while another 34% report being of German, English, or Scottish descent. These statistics are based on information obtained from the U.S. Department of Agriculture's National Agricultural Statistics Service.
The city of Marengo is primarily accessible by air and by highway. The IL Route 176 and IL Route 23 are major north-south thoroughfares. The town also has several airports and is located near several highways. Marengo has grown steadily over the past several decades, and its population grew by 3% on average every year between 1990 and 2007. According to the Chicago Metropolitan Agency for Planning, the city's population will grow to eighteen thousand by the year 2030.
The city is home to about 2,568 residents. The median household income in Marengo is $31,289. The average income in Marengo is $36,597. The median household income in the city is $31,289. Moreover, the average high school graduation rate is 81% and only 59% of people in Marengo dropped out of college. This is a relatively lower than average poverty rate in Iowa.
The city is the county seat of Marengo County. Its population was two thousand and seventy-three at the 2010 census. Its early inhabitants were German, Swiss, and French Huguenots. The town's first post office was named Riverside in 1885, but was renamed Myrtlewood after its famous crepe myrtlewood. It was incorporated as a town in 1957.