You know all about your local police force, the FBI, and other familiar law enforcement offices. The federal government operates lots of other police forces that don't get quite the same publicity in TV and movies; you might be surprised to learn that up until 2003, the Library of Congress had its own police! Here are a few of the specialized police forces you might not have even known were protecting you.

1. Supreme Court Police

If you're looking for a law enforcement job, you could do a lot worse than joining the 125-man force that protects the Supreme Court's justices as well as the Supreme Court building and any guests. The Supreme Court Police have been around since 1949, but they have only been allowed to carry weapons since former Chief Justice Warren Burger convinced Congress to beef up the force's powers in 1982. According to a 2004 Slate story, the pay's not bad, either; rookie Supreme Court Police officers earn up to 50% more than their counterparts in other federal police forces.

2. Department of Veterans Affairs Police

If anyone tries to make a stink at a VA hospital or medical facility, they'll have to deal with the VA's own police force. Since the VA has 170 facilities around the country, the force is pretty large; its ranks include over 3,000 officers. Hospital beats may not sound all that dangerous at first, but sadly five VA officers have lost their lives in shootings in the last 25 years.

3. National Oceanic and Atmospheric Administration Fisheries Office of Law Enforcement

Thinking of breaking the Atlantic Striped Bass Conservation Act of 1984? Think again.

The NOAA OLE has very specific authority to enforce 37 statutes that deal with fishing and marine resources. Over 200 special agents stationed around the country devote their workdays to making sure nobody goes after marine endangered species or tries any funny business with the importation of the Patagonian toothfish.

4. Amtrak Police

Want to take a picture of an Amtrak station? Keep the camera in your bag if you don't want to run afoul of the Amtrak Police. The force boasts nearly 350 members, all of whom are charged with keeping Amtrak's trains, stations, and facilities safe. They'll also stop you if you try to snap a photo at a station; since 9/11 Amtrak has cracked down on photography, lest the wrong people get a good look at their stations.

5. United States Postal Inspection Service

The USPIS is charged with cracking down on "crimes that may adversely affect or fraudulently use the U.S. Mail, the postal system or postal employees." Anyone trying to run a Ponzi scheme or pull off some other form of mail fraud should be worried about these guys; the USPS has over 1,500 agents protecting the integrity of the mail. They can investigate anything from fraud to mail theft to assaults on postal workers. On top of that, the USPIS has a 650-man security force that protects "critical postal facilities throughout the country" and "escorts high value mail shipments."

6. Smithsonian Police

The Smithsonian Institution's facilities are full of priceless artifacts, so it's only natural that it would have its own police force. The Smithsonian Museum Protection Officers are a special police force that has a very specific jurisdiction: within the outer curbs of the sidewalks surrounding the Smithsonian's facilities in Washington, D.C., New York City, and Panama. They're armed and ready to protect the Institution's holdings, though, so don't get any bright ideas about boosting The Spirit of St. Louis during your next trip to Washington.

7. US National Zoological Park Police

Someone's got to keep the animals at the National Zoo safe, and this force, which also falls under the umbrella of the Smithsonian Institution, provides round-the-clock protection of the zoo.

8. Bureau of Reclamation Police

The official name isn't so catchy, but this group is commonly known as the Hoover Dam Police. Since the Hoover Dam is built on land that Nevada ceded to the federal government for the project, law enforcement around the dam is the federal government's responsibility. When the dam was first built, the feds felt this was a one-man job, and U.S. Marshal Claude Williams took care of the entire region.

Over time, though, the security force grew. The Hoover Dam Police officers now have a 22-square-mile jurisdiction around the dam where they are responsible for both the security and integrity of the dam but also the enforcement of state and federal laws.

9. Tennessee Valley Authority Police

Apparently if you build enough dams, you'll need your own police force. The TVA Police protect not just the TVA's dams and facilities, but also the 100 million annual visitors to the TVA's recreation areas.

10. Federal Reserve Police

The Federal Reserve has quite a bit of cash in its coffers, so it's only natural that it needs its own specialized force to help protect it. The thousand-plus members of the Federal Reserve Police patrol our central bank's 12 regional offices and protect members of the Fed's board.

11. United States Mint Police

Like the Fed, the United States Mint is sitting on a lot of loot, and the Mint Police make sure nobody runs off with any of it. The Mint Police have been around since 1792—even in the nation's early days, someone needed to keep tabs on the gold—and currently safeguards $100 billion worth of the Treasury's assets at the various mints around the country as well as at Fort Knox and West Point, NY.

12. United States Park Police

No, they're not the same as National Park Rangers. The Park Police is a specialized police force that serves as the long arm of the law at certain National Park Service sites in Washington, D.C., New York, and San Francisco. George Washington himself actually recruited an early version of the Park Police in 1791 to help guard certain national landmarks, and today they're charged with keeping us safe on thoroughfares like the National Mall and the Baltimore-Washington Parkway Greenbelt.