Locked up tighter than Fort Knox.

The phrase-a reference to the heavily guarded gold bullion depository at Fort Knox, Ky.-has become shorthand for the ultimate in security and asset protection. The officers who provide that celebrated protection are part of a relatively unknown federal law enforcement agency: the United States Mint Police.

Most Americans are familiar with the duties of mounted U.S. Park police, overworked Border Patrol agents, dark-suited Secret Service agents, and anti-terrorist Federal Air Marshals. But the Mint Police, not so much.

The force employs hundreds of sworn officers who protect and serve at six U.S. Mint facilities across the United States in Washington, D.C.; Philadelphia; Denver; San Francisco; Fort Knox; and the silver, gold, and platinum bullion depository in West Point, N.Y. In addition to guarding $100 billion in gold, silver, and U.S. coins, Mint police have also protected such unique holdings as the U.S. Constitution, Lincoln's Gettysburg Address, and, until 1978, the crown jewels of King Stephen the Great of Hungary.

"A U.S. Mint police officer is not a typical police officer," emphasizes Sgt. Adrienne Meyer, who is stationed at the U.S. Bullion Depository in Fort Knox. "Mint Police are charged with securing and protecting our nation's precious metals, monetary and other physical assets, and protecting the employees of the U.S. Mint."

The chain of Mint facilities is impressive, with various functions at differing locations. Some facilities, like Fort Knox, provide asset protection. Others produce, or mint, general circulation coins, commemorative coins and medals, or uncirculated bullion coins. Production facilities in Denver and Philadelphia alone produce 65 million to 80 million coins per day.

Increasingly, the department has broadened its policing mission beyond the walls of federal Mint facilities. Mint officers train with local law enforcement agencies in their respective cities, and have created bicycle patrols that bring officers into contact with local businesses and members of the general public on city streets.

The department has also created U.S. Mint Special Response Teams, which can be mobilized to various locations across the nation. In the past few years, officers have participated in security details at a variety of non-Mint-related events, including two presidential inaugurations, the Kentucky Derby, 2002 Winter Olympics in Salt Lake City, an auction at Sotheby's in New York City, and an International Monetary Fund/ World Bank Conference.

"We've grown and evolved from an interior-fixed-post environment to policing on the federal, city, state, national, and international levels," says U.S. Mint Police Officer Laundres "Lonnie" Carter, a six-year department veteran who works at the U.S. Mint in Philadelphia.

Police from all Mint facilities were deployed to assist with Hurricane Katrina relief efforts-not only by providing security at the New Orleans Federal Reserve Bank, but also providing needed support services. Mint officers, who worked alongside local police agencies and area National Guard troops, were also tasked with safeguarding and escorting critical food, water, and fuel supplies through ravaged city streets.

"We have done more to establish solid working relationships with the local, state, and federal law enforcement agencies around each of our facilities," says Meyer, who served as an Army military police investigator, U.S. Army Criminal Investigation Command special agent, and Department of Veterans Affairs police officer before coming to the Mint Police Department.

Damage caused by Hurricane Katrina and other natural disasters, as well as the events of Sept. 11, "made most law enforcement agencies realize how much we need and have to depend on each other to protect our nation and her citizens," Meyer says.

The U.S. Mint Police Department is working to actively recruit officers from the private and public sector. Officers' pay has been increased, along with opportunities for advanced training-including cross training with other law enforcement agencies, per National Incident Management System (NIMS) guidelines.

"The diversity of our duties makes each day exciting," says Carter, who came to the department with prior experience as a U.S. Air Force law enforcement specialist/instructor, private investigator, dignitary protection specialist, and Federal Reserve Bank police officer. "(It) presents us the opportunity to work with and learn from some of the best people within our agency-and throughout the world."

Bryn Bailer, a former newspaper reporter, is a contributing editor for Police. By night, she is a member of the Tucson Police Department Communications Division.