The federal court system includes 94 district courts in the 50 states, Washington, D. C., Puerto Rico, Guam, U.S. Virgin Islands, and Northern Marinara Islands. Most states have only one judicial district. Larger states can have between two and four districts. The district courts serve as the general trial courts of the federal system. Each district also has a bankruptcy unit, as district courts have exclusive jurisdiction over bankruptcy cases.

District courts generally have jurisdiction to hear cases involving federal law and those involving citizens of different states. If a party in a state case can prove that a federal district court has jurisdiction to hear a case, the party may remove the case to the federal court. However, the federal court may abstain from hearing a case that involves questions of both federal law and state law. A situation may also arise where a federal district court may no longer have jurisdiction to hear a case because of changes in the parties to the suit. If a case has been removed to federal district court and the federal district court lacks jurisdiction, the court on motion of one of the parties will remand the case to the appropriate state court.