Interpol (International Criminal Police Organization), a cooperative association of more than 170 national law-enforcement agencies. (The United States is represented by an official of the Treasury Department.) Interpol keeps records on international criminals and maintains a vast communications network for exchanging police information. It does not employ investigators, but members often conduct investigations for each other. Interpol was formed in Vienna in 1923 and reestablished in Paris in 1946. Headquarters are in Lyon, France.