In the United States, a federal crime or federal offense is a crime that is either made illegal by U.S. federal legislation (Title 18 of the United States Code) or a crime that occurs on U.S. federal property.

The term "federal offence" has a separate meaning in Canada.

The Federal Bureau of Investigation (FBI) has been granted powers to investigate federal offenses.

Mail fraud which crosses state lines or involves the (national) United States Postal Service is a federal offense. Other federal crimes include kidnapping, tax evasion, counterfeiting, theft of major artwork from a museum,[1] damaging or destroying mailboxes, immigration offenses, and since 1965, assassinating the President or Vice President, although these were not made federal crimes until after President John F. Kennedy's assassination.

In drug-related federal offenses mandatory minimums can be enforced. A mandatory minimum is a federally regulated minimum sentence for offenses of certain drugs.

Prosecution guidelines are established by the United States Attorney in each federal judicial district and by laws that Congress has already established.