Which organization investigates counterfeiting in the United States?

The Secret Service is the organization responsible for investigating counterfeiting in the United States. Originally created in 1865 to combat the widespread counterfeiting of U.S. currency, the Secret Service has maintained this responsibility as part of its mission. Their role includes investigating and preventing fraud involving the nation's financial infrastructure, which encompasses counterfeit currency as well as other financial crimes related to the protection of the U.S. monetary system.

While the Federal Bureau of Investigation has a broader mandate that includes various criminal investigations, and the Department of Treasury oversees financial and monetary policies, the Secret Service specifically focuses on counterfeiting and related financial crimes. Homeland Security also addresses a wide range of security issues, but it does not have the primary responsibility for counterfeiting investigations, which remain under the jurisdiction of the Secret Service.