Many people ask, What is a federal offense, when trying to understand how certain criminal cases are handled in the United States legal system. What is a federal offense generally refers to a crime that violates federal law, occurs across state lines, involves federal agencies, or takes place on federal property. Common examples include tax fraud, drug trafficking, identity theft, mail fraud, bank robbery, cybercrime, and certain firearm-related offenses. Federal crimes are prosecuted in federal court and often carry serious penalties, including fines, probation, or prison time depending on the nature and severity of the offense.