The Pinkerton's National Detective Agency, more colloqually known as the Pinkertons are a private investigation and security company established around 1850 in the United States by Scottish-born American cooper Allan Pinkerton and Chicago attorney Edward Rucker as the North-Western Police Agency, which later became Pinkerton & Co. and finally the Pinkerton's National Detective Agency.

Though the height of its power was from the 1870s to the 1890s as the, at the time, largest private law enforcement organization in the world, it still holds significant power and influence, especially in its home turf of Chicago.

Though not officially involved in the Labor Battles, the Pinkertons are well known as a strike breaking organization, so their agents are - for as far as they are known - not welcome at Union meetings.

The head of the Pinkertons in Chicago is Francis Dimaio, with Allan Pinkerton II, the grand son of the agencies founder, heading the organization from New York.