Federal law enforcement agencies are highly specialized organizations. They are structured to enforce specific statutes in the U.S. Criminal Code. 

Department of Justice

• Federal Bureau of Investigation (FBI)
   
• Federal Drug Enforcement Administration (DEA)
   
• United States Marshals Service
   
• Immigration and Customs Enforcement (ICE)

Department of the Treasury

• Internal Revenue Service (IRS)
   
• United States Secret Service (SS)
   
• United States Customs Service
   
• Bureau of Alcohol Tobacco and Firearms (ATF)
   
• Federal Law Enforcement Training Center

Department of the Interior

• Fish and Wildlife Service
   
• National Park Service

Department of Transportation

• United States Coast Guard

U.S. Postal Service

• United States Postal Inspection Service