U.S. Secret Service and Postwar Counterfeiting, 1865–1870

The United States Secret Service was established in 1865 within the Treasury Department, initially focusing on counterfeit currency rather than presidential protection. The Civil War had left a fragmented monetary system in which false notes circulated widely and damaged confidence in federal finance.

Agents worked through informants, surveillance and raids against printers, distributors and organised networks. Investigations often crossed state lines and involved veterans and civilians whose wartime experience shaped the postwar economy.

Historical fiction uses this early mission for stories of hidden money, compromised respectability and new federal authority. The Keys to Gramercy Park connects a veteran agent with counterfeit notes discovered in a modern Manhattan apartment.