Cicero is a town in Cook County, Illinois, United States, and a suburb of Chicago. As of the 2020 census, the population was 85,268, making it the 11th-most populous municipality in Illinois. The town is named after Marcus Tullius Cicero, a Roman statesman and orator.

Originally, Cicero Township occupied an area six times the size of its current territory. The cities of Oak Park and Berwyn were incorporated from portions of Cicero Township, and other portions, such as Austin, were annexed into the city of Chicago.

By 1911, an aerodrome called the Cicero Flying Field had been established as the town's first aircraft facility of any type, located on a roughly square plot of land about 800 meters (1/2-mile) per side, on then-open ground at 41°51′19.03″N 87°44′56.5″W / 41.8552861°N 87.749028°W / 41.8552861; -87.749028 by the Aero Club of Illinois, founded on February 10, 1910. Famous pilots like Hans-Joachim Buddecke, Lincoln Beachey, Chance M. Vought and others flew from there at various times during the "pioneer era" of aviation in the United States shortly before the nation's involvement in World War I; the field closed in mid-April 1916.

After building his criminal empire in Chicago, Al Capone moved to Cicero to escape the reach of Chicago police. The 1924 Cicero municipal elections were particularly violent due to gang-related efforts to secure a favorable election result.

On July 11–12, 1951, a race riot erupted in Cicero when a white mob of around 4,000 attacked and burned an apartment building at 6139 W. 19th Street that housed the African-American family of Harvey Clark Jr., a Chicago Transit Authority bus driver who had relocated to the all-white city. Governor Adlai E. Stevenson was forced to call out the Illinois National Guard. The Clarks moved away and the building had to be boarded up. The Cicero riot received worldwide condemnation.

Cicero was taken up and abandoned several times as site for a civil rights march in the mid-1960s. Cicero had a sundown town policy prohibiting African Americans from living in the city. The American Friends Service Committee, Martin Luther King Jr., and many affiliated organizations, including churches, were conducting marches against housing and school de facto segregation and inequality in Chicago and several suburbs, but the leaders feared too violent a response in Chicago Lawn and Cicero. Eventually, a substantial march (met by catcalls, flying bottles and bricks) was conducted in Chicago Lawn, but only a splinter group, led by Jesse Jackson, marched in Cicero. The marches in the Chicago suburbs helped galvanize support for the passage of the Civil Rights Act of 1968, extending federal prohibitions against discrimination to private housing. The act also created the United States Department of Housing and Urban Development's Office of Fair Housing and Equal Opportunity, which enforces the law.

The 1980s and 1990s saw a heavy influx of Hispanic (mostly Mexican and Central American) residents to Cicero. Once considered mainly a Czech or Bohemian town, most of the European-style restaurants and shops on 22nd Street (now Cermak Road) have been replaced by Spanish-titled businesses. In addition, Cicero has a small black community.

Cicero has seen a revival in its commercial sector, with many new mini-malls and large retail stores. New condominiums are also being built in the city.

Cicero has long had a reputation of government scandal. In 2002, Republican Town President Betty Loren-Maltese was sent to federal prison in California for misappropriating $12 million in funds.

According to the 2021 census gazetteer files, Cicero has a total area of 5.87 square miles (15.20 km2), all land. Cicero formerly ran from Harlem Avenue to Western Avenue and Pershing Road to North Avenue; however, much of this area was annexed by Chicago.

As of the 2020 census there were 85,268 people, 22,698 households, and 17,508 families residing in the town. The population density was 14,538.45 inhabitants per square mile (5,613.33/km2). There were 25,836 housing units at an average density of 4,405.12 per square mile (1,700.83/km2). The racial makeup of the town was 19.22% White, 3.72% African American, 4.26% Native American, 0.59% Asian, 0.04% Pacific Islander, 46.86% from other races, and 25.30% from two or more races. Hispanic or Latino of any race were 89.00% of the population.

There were 22,698 households, out of which 45.5% had children under the age of 18 living with them, 47.83% were married couples living together, 19.60% had a female householder with no husband present, and 22.87% were non-families. 18.99% of all households were made up of individuals, and 5.63% had someone living alone who was 65 years of age or older. The average household size was 4.06 and the average family size was 3.55.

The town's age distribution consisted of 28.0% under the age of 18, 12.3% from 18 to 24, 28.2% from 25 to 44, 23.2% from 45 to 64, and 8.5% who were 65 years of age or older. The median age was 31.7 years. For every 100 females, there were 96.9 males. For every 100 females age 18 and over, there were 98.9 males.

The median income for a household in the town was $53,726, and the median income for a family was $56,632. Males had a median income of $33,835 versus $26,101 for females. The per capita income for the town was $20,040. About 11.4% of families and 13.8% of the population were below the poverty line, including 18.3% of those under age 18 and 15.3% of those age 65 or over.

As of 2011, 52.5% of occupied housing units were owned properties, and 47.5% were rentals. There were 4,667 vacant housing units. The average age of home properties was greater than 66 years.

Cicero is a factory town. As of 1999, about a quarter of the city contained one of the greatest industrial concentrations in the world. There were more than 150 factories in 1.7 mi (2.8 km), producing communications and electronic equipment, sugar, printing presses, steel castings, tool and die makers' supplies, forging and rubber goods.[citation needed]

On the south side of Cicero, there were two racetracks. Hawthorne Race Course, located in Cicero and Stickney, is a horse racing track still in operation. Just north of it was Chicago Motor Speedway at Sportsman's Park, which was formerly Sportsman's Park Racetrack (for horse racing) for many years. This Sportsman's Park facility is now closed, acquired by the Town of Cicero, and has since been demolished. Facilities of the Wirtz Beverage Group have been built on the west half and a Walmart built on the east half.

Most of Cicero is in Illinois's 4th congressional district; the area south of the railroad at approximately 33rd Street is in the 3rd district.

The United States Postal Service operates the Cicero Post Office at 2440 South Laramie Avenue.

Cicero is served by Cicero Elementary School District 99 and comprises 16 schools, making it one of the largest public school districts outside of Chicago. Elementary students attend the following schools, depending on residency: Burnham (K-6), Cicero East (4-6), Cicero West (PK-4), Columbus East (4-6), Columbus West (PK-4), Drexel (K-6), Early Childhood Center (PK), Goodwin (PK-6), Liberty (K-3), Lincoln (PK-6), Roosevelt (5-6), Sherlock (PK-6), Warren Park (PK-6), Wilson (K-6), and Unity Junior High (7-8), which is separated into East/West sections. East side being held for eighth graders & seventh graders on the West side. Unity is the second largest middle school in the country. High school students entering their freshman year attend the Freshman Center and then continue high school at Morton East of the J. Sterling Morton High School District 201. The McKinley Educational Center serves as an alternative school for 5th-8th graders and the Morton Alternative School serves as an alternative school for 9th-12th graders

The Roman Catholic Archdiocese of Chicago operates one PK-8 school in Cicero, Our Lady of Charity School. St. Frances of Rome School closed in 2024.

From 1927 until 1972, Cicero was the home of Timothy Christian School.

Cicero is also home to Morton College.

Cicero is served by two major railroad lines, the BNSF Railway and the Belt Line Railroad. Public Transportation is provided by Metra's BNSF Line between Aurora and Chicago's Union Station with a stop at the Cicero station near Cicero Avenue and 26th Street. Currently, this station is undergoing a much needed reconstruction and expansion by Metra. Also, the CTA Pink Line provides daily service from the 54th/Cermak terminal to the Loop. Its Cicero station is also located in Cicero. Multiple Pace and CTA bus routes cover portions of Cicero.

The Cicero Fire Department (CFD) has a staff of 97 professional full time firefighters. The CFD operates out of three fire stations.