The Chicago Police Department, also known as Chicago P.D. and the CPD, is the main law enforcement agency of the City of Chicago, Illinois, in the United States, under the jurisdiction of the city mayor. It is the largest police department in the Midwest and the second largest in the United States after the New York City Police Department with over 13,600 sworn officers and over 2,600 other employees. Dating back to 1837, the Chicago Police Department is one of the oldest modern police forces in the world.