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Pinkertons: Topics in Chronicling America

In the late 19th century, private police forces battled against organized labor groups. This guide provides access to material related to the "Pinkertons" in the Chronicling America digital collection of historic newspapers.


"Pinkerton Men Running the Gauntlet." July 8, 1892. Pittsburg Dispatch (Pittsburg, PA), Image 1. Chronicling America: Historic American Newspapers.

What began as a detective agency in Chicago grew into a national private police force. The Pinkertons stood against organized labor at nearly every turn from Haymarket to Homestead and famously took down the Molly Maguires, while instilling fear in the hearts of fugitives across the country. Read more about it!

The information in this guide focuses on primary source materials found in the digitized historic newspapers from the digital collection Chronicling America.

The timeline below highlights important dates related to this topic and a section of this guide provides some suggested search strategies for further research in the collection.


January 26, 1875 Pinkerton detectives raid a farm house in search of Frank and Jesse James. During the failed raid, the Pinkerton detectives threw a hand grenade into the house, killing their younger brother and severing their mother’s arm.
June 21, 1877 7 members of the Molly Maguires are executed due to the testimony of Pinkerton Detective, James McParlan, who successfully infiltrated the Mollies.
July 1, 1884 Allan Pinkerton, founder of Pinkerton National Detective Agency, dies in Chicago, IL.
July 24, 1886 Andrew Johnson, a Pinkerton detective who had been undercover with the International Workingmen’s Union, is called to testify in the Haymarket bombing trial.
July 6, 1892 Pinkerton men are called in by Carnegie to break the Homestead Strike. After a 13 hour firefight, the Pinkertons surrender unconditionally to the strikers.
July 8, 1892 Kentucky General Assembly introduces a bill to ban the employment of Pinkertons in Kentucky.
July 28, 1892 Billy and Robert Pinkerton are called to testify before Congress about the Homestead incident.