Biohazard Cleanup Near Summit Historic District Summit, IL

Summit is a city in Cook County, Illinois, on Chicago's southwest border, where Harlem Avenue separates it from the city of Chicago.

Summit's name, in use since 1836, refers to the highest point on the Chicago Portage — the divide between the northeast-flowing Chicago River and the southwest-flowing Des Plaines River just north of the city.

The Marquette and Joliet expedition passed through the portage by present-day Summit in 1673, recognizing its importance as a link between the Great Lakes and the Mississippi River system.

The Illinois and Michigan Canal was dug through the settlement between 1836 and 1848, and many of its Irish canal laborers bought land in Summit with their canal script pay.

Summit was incorporated in 1890, in part because residents feared annexation by Chicago after the death of landowner and former Chicago mayor "Long John" Wentworth.

Summit annexed the Argo neighborhood in 1911 — a company-town subdivision named for the Corn Products cornstarch plant, which when construction began in 1907 was the world's largest corn-processing plant.

The Argo plant, now run by Ingredion, remains one of the largest corn milling facilities of its kind in the world, and the adjoining ACH Food Companies plant produces Mazola corn oil, Karo syrup, and Argo corn starch.

Summit had a population of 11,161 in the 2020 census.

Summit had 3,269 households in the 2020 census, with an unusually large average household size of 3.92 people.

Summit is one of the most heavily Hispanic communities in Cook County — 72.75% of residents identified as Hispanic or Latino in the 2020 census.