Federal crimes are criminal offenses based on legislation (laws or statutes) enacted by the United States Congress and published in the United States Code (U.S.C.). Most crimes (murder, rape, assault, burglary, etc.) are prosecuted under state law (statutes) and are known as state law crimes. In contrast, crimes prosecuted under federal law are known as federal crimes.

Federal crimes generally involve a subject over which the United States Constitution gives the federal government—and more specifically, the U.S. Congress—the power or authority to legislate or make laws. This power or authority is also known as jurisdiction.

For example, the federal government (and not the states ) has the exclusive authority to print money and regulate its value. And because bank deposits are guaranteed (insured) by the federal government (FDIC) up to $250,000 per depositor, per FDIC-insured bank, and per ownership category, bank robbery is a federal crime (18 U.S.C. §2113). Examples of other federal crimes include tax evasion, wire fraud, mail fraud, immigration offenses, voting or electoral fraud, counterfeiting money, espionage (spying), and damaging or destroying mailboxes.

In Delaware, as in all states, federal crimes are distinct from state crimes and are prosecuted under the authority of the United States government. Federal crimes are based on laws passed by the U.S. Congress and are codified in the United States Code (U.S.C.). These offenses typically involve matters under federal jurisdiction, which means they pertain to areas where the U.S. Constitution grants the federal government the power to legislate. Examples of federal crimes include bank robbery, due to the federal insurance of bank deposits by the FDIC, as well as tax evasion, wire fraud, mail fraud, immigration offenses, and others. Federal agencies such as the FBI, DEA, and ATF, in conjunction with the U.S. Attorney's Office, are responsible for the investigation and prosecution of federal crimes. It's important to note that while the state of Delaware has its own criminal statutes, federal law supersedes state law in matters of federal jurisdiction.