Inside Chicago's gangland empire: Eye-opening map details exactly where the city's most notorious mobsters hid from the police and carried out their crimes in the roaring 20s 

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An incredible hand-drawn map from the 1920s reveals just how Chicago's infamous mobsters controlled the city.

Every clubhouse, home base, and hideout used by the more than 1,300 active gangs between 1923 and 1926 was marked down on a map spanning the entire city by a University of Chicago sociologist.

Frederic Thrasher put the amazingly detailed map together for part of a book he wrote chronicling the city's mobster scene, The Gang, a Study of 1313 Gangs in Chicago.

Chicago is well known for its bloody history with gangs, with the likes of Al Capone, George Moran, and John Dillinger operating in the city at stages during the 1920s and 1930s.

This map from the 1920s plotted exactly where gang hideouts and different territories were located across Chicago

A full map of the Second City is covered with hundreds of red triangles and dots, which are used to identify clubhouses with or without 'clubrooms', respectively. 

It then goes into even greater detail, marking out specific areas where specific ethnicities were dominant, including: 'Jewish', 'Polish', 'Negro, Hungarian', 'German', and others.

Further detail is provided by identifying important areas across the city, as well as know gang locations.

'No less than 1,313 gangs have been discovered in Chicago and its environs!' Frederic Thrasher wrote at the time, according to Atlas Obscura.

Some of the most infamous mobsters, including Al Capone (left) and George Moran operated across Chicago during the decade. Capone and Moran were rivals in the Chicago mafia

The map showed exactly where different mob locations were across the city. Pictured is a group of men in the street in 1920

'Their distribution as shown on the accompanying map makes it possible to visualize the typical areas of gangland and to indicate their place in the life and organization of Chicago.

'Gangland is a phenomenon of human ecology. The gang develops as one manifestation of the economic, moral, and cultural frontier which makes the interstice.' 

In his book, Thrasher claimed more than 25,000 boys and men were involved in gangs at the time, and the crews grew to the extent they became 'mini-societies'.

The mob expert then went on to write: 'No two gangs are just alike. Some are good; some are bad; and each has to be considered to its own merits.' 

The Birger Gang poses for a group portrait at its hangout, Shady Rest, Illinois. Many notorious gangs and mobsters operated in the city

Lester Gillis aka Babyface Nelson, a member of the Dillinger gang and regarded as the most psychotic outlaw of the 1930s, on an undertaker's slab as police stand over him

A wanted poster for Lester Gillis, the mobster who was known as 'Babyface' is seen in June 1934

The map charted where different gangs operated for three years between 1923 and 1926. Pictured in Chicago's Wrigley Field in the 1920s