Illinois's 3rd congressional district includes parts of Cook County and DuPage County, and has been represented by Democrat Delia Ramirez since January 3, 2023. The district was previously represented by Marie Newman from 2021 to 2023, Dan Lipinski from 2005 to 2021, and by Lipinski's father Bill from 1983 to 2005.

The district includes the western and southwestern suburbs of Chicago as far as the DuPage County border, as well as portions of the Southwest Side of the city of Chicago itself, and covers 124.5 square miles (322 km²), making it one of the 50 smallest districts in the U.S., although there are five smaller districts in Illinois. It is adjacent to the 1st district to the east and south, the 4th district to the north, and the 11th district to the west, and also borders the 6th and 7th districts at its northwestern and northeastern corners, respectively. The district was created following the 1830 census and came into being in 1833, five months before Chicago was organized as a town; it initially included northern and western Illinois^[3] before representing areas of east-central and northwestern Illinois from 1843 to 1873.^[4][5][6] The district has included part of Chicago since 1873, and part of the city's southwest side since 1895; the district has been primarily suburban since 1973.

The district includes the municipalities of Bedford Park, Bridgeview, Burbank, Chicago Ridge, Countryside, Forest View, Hickory Hills, Hodgkins, Hometown, Indian Head Park, Justice, La Grange, La Grange Park, Lyons, McCook, Merrionette Park, Oak Lawn, Palos Hills, Riverside, Stickney and Summit, nearly all of Berwyn, Brookfield, Western Springs and Willow Springs, and parts of Alsip, Burr Ridge, Cicero, Darien, Hillside, North Riverside, Orland Hills, Palos Heights, Palos Park, Westchester and Worth.

In the City of Chicago, it includes the communities of Bridgeport (home of mayor Richard M. Daley until he relocated in the late 1990s to the Near South Side's Central Station development), Clearing, Garfield Ridge, Mount Greenwood and West Lawn; almost all of Beverly; those portions of Archer Heights and West Elsdon west of Pulaski Road; the western portions of Ashburn, Chicago Lawn and Morgan Park; the portion of McKinley Park south of Archer Avenue; parts of Gage Park and New City; and a small section (1/16 mi²) of Armour Square.

The district is a historic U.S. transportation and shipping hub; not only does it include Chicago Midway International Airport, but it is also traversed by the Chicago Sanitary and Ship Canal, the Calumet Sag Channel, and the Des Plaines River, earning national designations for the Chicago Portage National Historic Site in Forest View and the Illinois and Michigan Canal National Heritage Corridor. The path of historic Route 66 runs southwest through the district from its eastern end in Chicago. Interstate 55 intersects with both the Tri-State Tollway (Interstate 294) and the Dan Ryan Expressway (Interstate 90/94) in the district, and in 2001 – since which time the district has shifted slightly to the northwest – it was noted as likely having more freight yards and railroad crossings than any other district.^[8]

The district includes SeatGeek Stadium, home of the Chicago Red Stars team in Women's Professional Soccer, as well as Hawthorne Race Course; the area also benefits from Chicago White Sox home games at U.S. Cellular Field, which is less than 1,000 feet (300 m) beyond the district's border. Portions of the Cook County Forest Preserves cover several square miles in the district's southwest corner. Cultural attractions include Brookfield Zoo and the Balzekas Museum of Lithuanian Culture in West Lawn; educational institutions include St. Xavier University in Mount Greenwood, Moraine Valley Community College in Palos Hills, Morton College in Cicero, and Richard J. Daley College, a Chicago city college, in West Lawn; and medical facilities include Advocate Christ Medical Center in Oak Lawn, Adventist La Grange Memorial Hospital in La Grange and MacNeal Hospital in Berwyn. A Ronald McDonald House adjacent to Advocate Christ opened in December 2008.^[12][13] Industrial and business presences in the district include: Tootsie Roll Industries; Electro-Motive Diesel; a Nabisco bakery which is the largest biscuit bakery in the world;^[14] the Chicago Area Consolidation Hub of United Parcel Service and adjacent BNSF Railway yard;^[15] an ACH Food manufacturing plant (formerly part of Corn Products Company) in Summit;^[16] an Owens Corning roofing and asphalt plant in Summit; and a Nalco Chemical plant in Bedford Park. The former site of the International Amphitheatre, now an Aramark plant, is within the district. Organizations based in the district include the American Nuclear Society in La Grange Park. Among the federal facilities in the district is the Great Lakes Regional Headquarters of the National Archives and Records Administration^[17] in West Lawn.

Other district sites on the National Register of Historic Places include:

• American State Bank, Berwyn
• Berwyn Health Center
• Berwyn Municipal Building
• Avery Coonley House, Riverside
• Cornell Square, New City, Chicago
• Arthur J. Dunham House, Berwyn
• First Congregational Church of Western Springs
• Grossdale Station, Brookfield
• Haymarket Martyrs' Monument National Historic Landmark, Forest Park
• Hofmann Tower, Lyons
• La Grange Village Historic District
• Lyons Township Hall, La Grange
• Old Stone Gate of Chicago Union Stockyards National Historic Landmark, New City, Chicago
• George E. Purple House, La Grange
• Ridge Historic District, Beverly/Morgan Park, Chicago
• Riverside Landscape Architecture District, Riverside
• Robert Silhan House, Berwyn
• F.F. Tomek House, Riverside
• Wayne Village Historic District
• Western Springs Water Tower

The district has been described as "ancestrally Democratic, culturally conservative, multiethnic and viscerally patriotic."^[18] It earned a reputation as being home to Reagan Democrats when in the 1980 presidential election it was one of only two Chicago districts (out of nine) to be won by Republican Ronald Reagan, along with the 6th district (an almost entirely suburban district which also included Chicago's O'Hare Airport); the district simultaneously reelected Democratic congressman Marty Russo with nearly 69% of the vote.^[19] The Reagan Democrat description became even more appropriate when Reagan received 65% of the vote here in 1984 while Russo again won with 64%.^[20] Redistricting for the 1990s shifted the district into more reliably Democratic territory, but Bill Clinton won the district in 1992 by just a 41%-39% margin despite receiving at least 65% of the vote in four other south side districts; he won the district with 53% in 1996 although his totals in the other south side districts were all between 80 and 85%. George W. Bush received 41% of the vote here in both 2000 and 2004 despite not exceeding 21% in any of the other four south side districts; it was his best performance in any district located primarily within Cook County. Much of the district's current suburban territory was in the 4th district from the 1950s to the 1970s, when that was a solidly Republican suburban district represented by Ed Derwinski. More recently, Lyons, Palos and Riverside Townships in the western half of the 3rd district have all voted for Bush in 2000.^[21] Over the last eight presidential elections, the Democratic nominee for Congress has run an average of 20 points ahead of the party's nominee for president in the district.^[22]

Redistricting which took effect for the 1992 elections kept only 40% of the district's previous area, and pitted nine-term incumbent Russo – who changed his residence rather than run in the 2nd district, which now included his previous home – against five-term incumbent Bill Lipinski, who had previously represented the neighboring 5th district, in the Democratic primary. Lipinski ran close to Russo in the suburbs but easily won the Chicago areas, and won the primary 58%-37%.^[23] Lipinski was decidedly the most conservative Democrat in the Illinois delegation,^[18] opposing abortion and homosexual people serving in the military while supporting school prayer, tuition vouchers, the Defense of Marriage Act and the death penalty. He also helped to write a proposed constitutional amendment in 1997 prohibiting flag desecration.^[24][25] A member of the Blue Dog Democrats,^[25] he was one of just 30 Democrats to vote for the Republican welfare reform plan.^[8] He clashed often with the Clinton administration, opposing the president's position over half the time in the 1997-1998 Congress.^[26] He was one of 31 Democrats to vote in favor of a Judiciary Committee inquiry during the leadup to Clinton's impeachment; he eventually voted against impeachment, but simultaneously called on Clinton to resign.^[27] In 1999, Lipinski stated that Clinton "doesn't have credibility on military issues," adding that "the American people feel Clinton is unsure."^[25] He was a consistent opponent of U.S. free trade agreements, arguing that they were disastrous for American manufacturing.^[8][25] Lipinski received higher approval ratings from the American Conservative Union than from the ACLU in 12 of his last 13 years in office, though his highest ratings generally came from labor and consumer groups^[24][26] and the Christian Coalition.^[28] He received a 0 rating from the ACLU for the 1997–98 term,^[26] and also compiled an overall 0 rating from the National Abortion Rights Action League.^[28] His policies enabled him to work easily with Republicans; he was a candidate to become Transportation Secretary in the Bush administration, and collaborated with House Speaker Dennis Hastert of the 14th district to design the state's redistricting plan following the 2000 census.^[27] and after surviving with a 54%-46% win amid the Republican gains of 1994 he was reelected by increasing margins in each succeeding election; in 2002 he became the first unopposed candidate in the history of the district.^[29]

In the 2018 Republican primary, the only option was Arthur Jones, a self-proclaimed member of the Nazi party and holocaust denier. Although Jones received over 20,000 votes in the primary, many district GOP organizations took the unprecedented step of endorsing Rep. Dan Lipinski in the general election.^{[citation needed]}

This table indicates how the district has voted in U.S. presidential elections; election results reflect voting in the district as it was configured at the time of the election, not as it is configured today.

This table indicates how the district has voted in recent statewide elections; election results reflect voting in the district as it is currently configured, not necessarily as it was at the time of these elections.

• Illinois's congressional districts
• List of United States congressional districts