The United States district courts are the general trial courts of the United States federal court system. Both civil and criminal cases are filed in the district court, which is a court of both law and equity. There is a United States bankruptcy court associated with each United States district court. Each federal judicial district has at least one courthouse, and most districts have more than one. The formal name of a district court is "the United States District Court for" the name of the district -- for example, the United States District Court for the Southern District of New York.

There is at least one judicial district for each state, the District of Columbia, and Puerto Rico. District courts in three insular areas - the United States Virgin Islands, Guam, and the Northern Mariana Islands -"exercise the same jurisdiction as U.S. district courts." Despite their name, these courts are technically not "District Courts of the United States." Judges on these territorial courts do not enjoy the protections of Article Three of the Constitution, and serve terms of ten years rather than for life.