What Were The Two Oldest Federal Law Enforcement Agencies In America?

The United States Postal Inspection Service (USPIS) holds the distinction of being America’s oldest federal law enforcement agency, with a history dating back to the late 18th century. Its primary jurisdiction revolves around investigating and addressing criminal activities that either harm or involve fraudulent use of the U.S. Mail, the postal system, or postal employees. This agency has maintained its uninterrupted operation since its inception, making it a cornerstone of federal law enforcement efforts in safeguarding the integrity of the nation’s mail services.

The question of the oldest known law enforcement agency takes us back to the early days of the United States. While the U.S. Marshal’s Service, established in 1789, is the oldest federal law enforcement agency, the oldest NON-Federal law enforcement agency is the Boston Police Department, founded in 1838. The United States Marshal Service traces its origins to The Judiciary Act, a historic bill crafted by the inaugural Congress and signed into law by President George Washington in 1789. This act played a pivotal role in establishing the U.S. Marshal’s Service as an integral part of the federal law enforcement system, making it the oldest federal law enforcement agency in the United States. Meanwhile, the Boston Police Department has a separate and distinct history as the oldest non-federal law enforcement agency in the country, serving the city of Boston since 1838.