US SECRET SERVICE Department Of Home land Security Challenge Coin. This is a great looking SECRET SERVICE challenge coin. Coin is about 1 9/16" in diameter and raised lettering. Coin is contained in an acrylic air tight holder. The United States Secret Service (USSS) is an American federal law enforcement agency that is part of the U S Department of Homeland Security, The sworn members are divided among the Special Agents and the Uniformed Division. Until March 1, 2003, the Service was part of the U S Department of the Treasury. The U.S. Secret Service has two distinct areas of responsibility: Financial Crimes, covering missions such as prevention and investigation of counterfeiting of U S Currency and U S treasury securities, and investigation of major fraud. Protection, which entails ensuring the safety of current and former national leaders and their families, such as the President, past presidents, vice presidents, presidential candidates, visiting heads of state, and foreign embassies (per an agreement with the U.S. State Department's Bureau of Diplomatic Security (DS) Office of Foreign Missions (OFM), etc.) The Secret Service's initial responsibility was to investigate counterfeiting of U.S. currency, which was rampant following the U S Civil War. The agency then evolved into the United States' first domestic intelligence and counterintelligence agency. Many of the agency's missions were later taken over by subsequent agencies such as the Federal Bureau of Investigation, Bureau of Alcohol, Tobacco, Firearms and Explosives, U S Immigration and Customs Enforcement and Internal Revenue Service. Today the agency's primary investigative mission is to safeguard the payment and financial systems of the United States. These include crimes that involve financial institution fraud, computer and telecommunications fraud, false identification documents, access device fraud, advance fee fraud, electronic funds transfers and money laundering as it relates to the agency's core violations. After the 1901 assasination of President William McKinley, Congress also directed the Secret Service to protect the President of the United States. Protection remains the other key mission of the United States Secret Service.