District court and circuit courts are both trial courts where the facts of a litigated matter are usually presented to and decided by a jury. While both types of courts are trial courts, they are different in that each is in a separate judicial system, has the power to hear certain types of cases and abides by different procedure rules.
District courts are federal trial courts that have power to hear certain types of cases. Federal district courts have jurisdiction over cases between citizens of different states where the amount in controversy exceeds $75,000 or cases in which the issue being litigated centers on a statute that possibly violates the U.S. Constitution, a treaty signed by the United States or a law enacted by Congress. There are 94 federal district courts nationwide. Each state has at least one federal court with some states, like New York, having as many as four district courts to serve the northern, southern, eastern and western territories of the state. Federal district court decisions are appealable to the U.S. Court of Appeals.
Circuit courts are state trial courts that have the power to hear cases arising under the laws of that state and between citizens and/or businesses located in that state. These courts are created under the state's constitution and have jurisdiction to hear cases according to specified parameters. For example, Florida has 20 circuit courts. Each circuit encompasses a few counties and has the authority to hear civil disputes exceeding $15,000. Circuit courts also hear criminal cases and cases involving family law. Circuit court decisions are typically appealable to the state courts of appeal.
Trial courts have procedural rules that govern all aspects of a trial. From what cases the court may hear to how pleadings must be filed and the number of jurors that must be impaneled, attorneys from both sides must follow these rules or risk sanctions from the presiding judge. In general, district courts follow the Federal Rules of Civil Procedure. Circuit courts follow each circuit's own proscribed rules.
Another difference between district courts and circuit courts is the jury. Federal district courts require a jury to consist of at least six, but no more than 12, jurors. Each juror must participate in the decision (i.e., no alternates allowed) and the jury must also return a unanimous verdict. By contrast, state circuit courts often allow for smaller juries, the use of alternates and do not require verdicts to be anonymous.