federal offense
Any crime that occurs when crossing state lines can warrant federal charges. For example, traveling with drugs from Texas to New Mexico, or kidnapping a child and driving out of the state. Additionally, even if the defendant doesn't physically cross state borders, any crime that does can still be a federal offense
Most crimes that occur within a state's borders, or within three miles of its coastline, are prosecuted in state court. But some federally owned land rests entirely within one state's borders—if a crime occurs on that land, then it's typically a federal offense
This situation leads to forum shopping, as parties will try to have their civil or criminal case heard in the court that they perceive will be most favorable to them.