# North Side Gang
The North Side Gang was a Prohibition-era criminal organization based north of the [Chicago River](https://www.edgepedia.org/chicago-river), best known as the principal rival of [Al Capone](https://www.edgepedia.org/al-capone)'s South Side organization during the bootlegging wars of the 1920s.[1](https://historyrise.com/article/the-history-of-the-north-side-gang-and-its-battle-for-control-of-chicago-s-underworld/) Unlike the heavily Italian South Side syndicates, it maintained a distinctly Irish leadership core even as it absorbed members of other ethnicities.[1](https://historyrise.com/article/the-history-of-the-north-side-gang-and-its-battle-for-control-of-chicago-s-underworld/)
| Key fact | Detail |
|---|---|
| Origin | Emerged during the 1910s from smaller street crews operating north of the Chicago River[1](https://historyrise.com/article/the-history-of-the-north-side-gang-and-its-battle-for-control-of-chicago-s-underworld/) |
| Ethnic character | Irish-dominated leadership core, with members of other ethnicities absorbed[1](https://historyrise.com/article/the-history-of-the-north-side-gang-and-its-battle-for-control-of-chicago-s-underworld/) |
| Principal business | Bootlegging after the Eighteenth Amendment and Volstead Act took effect in 1920[1](https://historyrise.com/article/the-history-of-the-north-side-gang-and-its-battle-for-control-of-chicago-s-underworld/) |
| Best-known leader | Dean (Dion) O'Banion, murdered in 1924[2](https://www.researchgate.net/publication/258128124_Gangland_Killings_in_Chicago_1919-1933) |
| Signature attack | A 1926 convoy of cars sent against Capone's headquarters in Cicero[3](https://omnigraphics.com/wp-content/uploads/shopp_files/0807686-SP.pdf) |
| End of the war | The St. Valentine's Day massacre of 1929, in which Capone's South Side gang executed seven North Side members[4](https://blogs.loc.gov/maps/2022/07/mapping-the-gangs-of-chicago/) |
## Origins in Prohibition-era Chicago
The gang grew out of the volatile ethnic neighborhoods of Chicago in the 1910s, a period when the city's underworld was still fragmented among Irish, Italian, and Jewish factions. The name "North Side Gang" is often used broadly for the Irish-dominated coalition that fought Al Capone, but the group evolved from several smaller street crews operating north of the Chicago River.[1](https://historyrise.com/article/the-history-of-the-north-side-gang-and-its-battle-for-control-of-chicago-s-underworld/)
When [Prohibition](https://www.edgepedia.org/prohibition) became law across the United States in 1920, legitimate businesses could no longer serve alcohol, opening the way for illegal speakeasies and the underground businesses that supplied them.[4](https://blogs.loc.gov/maps/2022/07/mapping-the-gangs-of-chicago/) The rapid passage of the Eighteenth Amendment and the [Volstead Act](https://www.edgepedia.org/volstead-act) created a black-market bonanza for alcohol, and the North Side Gang capitalized on the opportunity.[1](https://historyrise.com/article/the-history-of-the-north-side-gang-and-its-battle-for-control-of-chicago-s-underworld/) [Competition](https://www.edgepedia.org/competition) over bootlegging markets turned so violent that gangs, alcohol, and crime became a permanent part of Chicago's reputation.[5](https://www.encyclopedia.chicagohistory.org/pages/2487.html)
## The war with Capone
The North Side Gang's chief adversary was the South Side organization of [Johnny Torrio](https://www.edgepedia.org/johnny-torrio) and Al Capone, which fought for control of illegal alcohol distribution within the city.[4](https://blogs.loc.gov/maps/2022/07/mapping-the-gangs-of-chicago/) The rivalry ran in both directions. When Capone's goons helped elect a Republican slate of candidates in Cicero in 1924, he needed to bring in additional men from [Dean O'Banion](https://www.edgepedia.org/dean-obanion)'s North Side Gang and others, an indication that the two organizations were not always in open conflict.[6](https://themobmuseum.org/blog/did-the-chicago-outfit-elect-john-f-kennedy-president/)
**O'Banion's murder.** Dean O'Banion, also recorded as Dion, led the North Siders until his murder in 1924, one of the major gangland killings of the period 1919 to 1933.[2](https://www.researchgate.net/publication/258128124_Gangland_Killings_in_Chicago_1919-1933)
**Escalation.** The North Side Gang proved more of a challenge to Capone than other rivals. In one 1926 assault, the North Siders sent a convoy of cars to attack Capone's headquarters in the Chicago suburb of Cicero.[3](https://omnigraphics.com/wp-content/uploads/shopp_files/0807686-SP.pdf) Efforts to consolidate control over bootlegging operations provoked the bloody "Beer Wars," a struggle eventually won by Capone.[7](https://southside.uchicago.edu/History/Policing.html)
**The St. Valentine's Day massacre.** The best-remembered event of the war came in 1929, when Capone's South Side gang executed seven members of the North Side Gang in the St. [Valentine's Day](https://www.edgepedia.org/valentines-day) massacre.[4](https://blogs.loc.gov/maps/2022/07/mapping-the-gangs-of-chicago/) The decade-long gang wars of the 1920s and early 1930s were later commemorated in sensational pictorial maps, including Bruce-Roberts, Inc.'s 1931 "map of Chicago's gangland," published the same year Capone was convicted on five counts of tax evasion.[4](https://blogs.loc.gov/maps/2022/07/mapping-the-gangs-of-chicago/)
## Context in Chicago's gang history
The North Side Gang operated within a broader landscape of Chicago organized crime. Frederic Milton Thrasher, a doctoral student in sociology at the University of Chicago, documented 1,313 gangs in the city in his 1927 study *The Gang*, and his 1923 "Chicago's gangland" map charted the distribution of gang activity, distinguishing gangs with clubrooms from gangs without.[4](https://blogs.loc.gov/maps/2022/07/mapping-the-gangs-of-chicago/) Bootlegging quickly became the largest source of illegal income and jobs in the city, and the numerous independent operators of the early Prohibition years were eventually organized into a cartel that divided sales territories, raised prices, and reduced consumer choice and product quality.[8](https://www.encyclopedia.chicagohistory.org/pages/1280.html) The North Side Gang's war with Capone was part of this consolidation, in which the South Side organization ultimately prevailed.[7](https://southside.uchicago.edu/History/Policing.html)
## References
1. [The History of the North Side Gang and Its Battle for Control of Chicago's Underworld, History Rise](https://historyrise.com/article/the-history-of-the-north-side-gang-and-its-battle-for-control-of-chicago-s-underworld/)
2. [Gangland Killings in Chicago, 1919-1933, ResearchGate](https://www.researchgate.net/publication/258128124_Gangland_Killings_in_Chicago_1919-1933)
3. [Defining Moments: Prohibition, Omnigraphics](https://omnigraphics.com/wp-content/uploads/shopp_files/0807686-SP.pdf)
4. [Mapping the Gangs of Chicago, Worlds Revealed, Library of Congress](https://blogs.loc.gov/maps/2022/07/mapping-the-gangs-of-chicago/)
5. [Bootlegging, Encyclopedia of Chicago](https://www.encyclopedia.chicagohistory.org/pages/2487.html)
6. [Did the Chicago Outfit elect John F. Kennedy president?, The Mob Museum](https://themobmuseum.org/blog/did-the-chicago-outfit-elect-john-f-kennedy-president/)
7. [Police: A Short History, University of Chicago](https://southside.uchicago.edu/History/Policing.html)
8. [Underground Economy, Encyclopedia of Chicago](https://www.encyclopedia.chicagohistory.org/pages/1280.html)
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*Topic: Encyclopedia › Society and history › Law and justice › Criminal law and penal justice › Offenses › Organized crime and trafficking › Mafia and crime syndicates › Mafia and cartels of the Americas*
*Initially written Sep 17, 2026 · Reviewed: Oct 25, 2026 · Edited: Oct 15, 2026; Oct 25, 2026 · Last review: Oct 25, 2026*
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