A lower level federal court is any federal court whose verdict could be brought to an appeals court. The US federal court system has three main levels: district courts (also known as trial court), circuit courts (or appellate courts), and the Supreme Court of the United States. There are 94 district courts, 13 federal circuit courts, and one Supreme Court throughout the entire country.

US Federal District Courts

U.S. district courts are trial courts. They hear cases from a broad range of issues. There are 94 federal judicial districts, and each state has at least one district. The district courts have jurisdiction to hear both civil and criminal cases, and almost all categories of federal cases. Each district court is under the jurisdiction of an appellate court known as the Court of Appeals.

US Federal Circuit Courts

The Courts of Appeals hear appeals from the lower courts called District Courts. There are 94 districts organized into 12 regional circuits, with a U.S. Court of Appeals (also known as a Circuit Court) in each district. 11 circuit courts handle more than one state. The 12th circuit court is the Court of Appeals for the District of Columbia Circuit, which is located in Washington, D.C. In addition, there is a 13th Court of Appeals for the Federal Circuit which is also located in Washington, D.C. It has nationwide jurisdiction over specialized cases, primarily international trade and cases involving federal tax.

The circuit courts are considered intermediate appellate courts. They do not handle jury trials and only handle cases where a party wants to appeal a decision that a district court judge made on their case. Before deciding whether to accept an appeal, circuit court judges use documents called "briefs" to review the case. Every case at the circuit court level is initially handled by a panel of three judges. The majority of decisions are decided by these panels, although a party can request a rehearing by a full panel consisting of all the circuit court judges. This is called an en banc.

Map U.S. Circuit Courts (source) — *Map U.S. Circuit Courts (source*)

Each party involved in the appeal must submit a brief to the circuit court judge which outlines the legal arguments at issue. Third parties with a relevant interest or expertise in the area can submit additional briefs, called “amicus briefs” (or, “friend of the court” briefs). The circuit court judges review the briefs. In certain cases, a judge will issue a decision based solely on the information they’ve gathered from the briefs. In other cases, the judge will request what is called a "oral argument" session, in which the attorneys for the parties are given the opportunity to argue the cases before them. This gives the judge the opportunity to ask more questions about the case.

Courts should typically rule the same way that they previously ruled on the same issue. This is a legal principle of determining points in litigation according to precedent and is known by the latin term “stare decisis” which translates "to stand by a decision." There are two types of precedent: “mandatory” and “persuasive.” Mandatory precedent, which a court is required to follow, is within the same jurisdiction and either comes from a higher court or from the same court in a previous case. Persuasive precedent is one in which a court is not bound, but is nonetheless relevant and important. Precedent is persuasive if it is from a different jurisdiction or if it is in the same jurisdiction but the facts or law of the case are somewhat different. Since courts are not bound by precedent in other circuits, it is not uncommon for courts in one circuit to rule differently than courts in another circuit. However, attorneys frequently argue that case law from other circuits should be persuasive authority, even if a court is not bound by it.

Circuit courts from different geographical locations tend to vote differently because of political or ideological differences and often develop reputations for tendencies to vote one way or another. For example, many believe that the Fourth Circuit in Richmond, Virginia has a more conservative lean than the Ninth Circuit based in San Francisco, which tends to take a much more liberal stance.