Chicago City Council in the context of "Mayor of Chicago"

The city of Chicago is divided into 77 community areas for statistical and planning purposes. Census data and other statistics are tied to the areas, which serve as the basis for a variety of urban planning initiatives on both the local and regional levels. The areas' boundaries do not generally change, allowing comparisons of statistics across time. The areas are distinct from but related to the more numerous neighborhoods of Chicago; an area often corresponds to a neighborhood or encompasses several neighborhoods, but the areas do not always correspond to popular conceptions of the neighborhoods due to a number of factors including historical evolution and choices made by the creators of the areas. As of 2020, Near North Side is the most populous of the areas with over 105,000 residents, while Burnside is the least populous with just over 2,500. Other geographical divisions of Chicago exist, such as the "sides" with origin in the 3 branches of the Chicago River, the 50 wards of the Chicago City Council which undergo redistricting based in population movements, and the parishes of the Roman Catholic Church.

The Social Science Research Committee at the University of Chicago defined the community areas in the 1920s based on neighborhoods or groups of related neighborhoods within the city. In this effort it was led by sociologists Robert E. Park and Ernest Burgess, who believed that physical contingencies created areas that would inevitably form a common identity. Except for the addition of two areas (O'Hare from land annexed by the city in 1956 and Edgewater's separation from Uptown in 1980) and peripheral expansions due to minor annexations, the areas' boundaries have never been revised to reflect change but instead have been kept stable. The areas have become a part of the culture of Chicago, contributing to its perception as a "city of neighborhoods" and breaking it down into smaller regions for easier analysis and local planning. Nevertheless, Park's and Burgess's ideas on the inevitability of physically related areas forming a common bond have been questioned, and the unchanging nature of the areas has at times been seen as analytically problematic with major subsequent changes in some of the areas' urban landscapes, such as the construction of expressways.

The City Hall-County Building, commonly known as City Hall, is a 12-story building in Chicago, Illinois, that houses the seats of government of the City of Chicago and Cook County. The building's west side (City Hall, 121 N. LaSalle St.) holds the offices of the mayor, city clerk, and city treasurer; some city departments; offices of alderpersons of Chicago's 50 wards; and the Chicago City Council's chambers. The building's east side (County Building, 118 N. Clark St.) houses offices of the Government of Cook County, including the Cook County Board of Commissioners' chambers.

The building spans a city block bounded by Randolph Street to the north, Washington Street to the south, Clark Street to the east, and LaSalle Street to the west. It is the seventh building to serve as Chicago's city hall, the fourth built at its location, and the third shared by the governments of Chicago and Cook County. Its location has served as the seat of the city and county governments since 1853, except for a period from 1871—when the Great Chicago Fire destroyed the building—to 1885.

The government of the City of Chicago, Illinois, United States is divided into executive and legislative branches. The Mayor of Chicago is the chief executive, elected by general election for a term of four years, with no term limits. The mayor appoints commissioners and other officials who oversee the various departments. In addition to the mayor, Chicago's two other citywide elected officials are the City Clerk and the City Treasurer.

The City Council is the legislative branch and is made up of 50 alderpersons, one elected from each ward in the city. The council takes official action through the passage of ordinances and resolutions and approves the city budget. Government priorities and activities are established in a budget ordinance usually adopted each November.

The city clerk of Chicago is in charge of record-keeping for Chicago, including for its elections, permits, licenses, and laws. When the Chicago City Council is in session, the city clerk also serves as council secretary. The clerk is a citywide elected office, and is one of three city-wide elected officials in the City of Chicago, along with the Mayor and the Treasurer.

The current city clerk is Anna Valencia.

The Chicago Police Department (CPD) is the primary law enforcement agency of the city of Chicago, Illinois, United States, under the jurisdiction of the Chicago City Council. It is the second-largest municipal police department in the United States, behind the New York City Police Department. As of 2025 CPD had 11,554 sworn officers on duty, and has 124 units. Tracing its roots to 1835, the Chicago Police Department is one of the oldest modern police departments in the world.

The Chicago Police Department has a history of police brutality, racial profiling, misconduct, corruption, and the torture of multiple people in custody in the 1980s. In 2017, the US Department of Justice criticized the department for poor training, lack of oversight, and repeated incidents of excessive force.