The U.S. Courts of Appeals are a group of federal courts that review decisions made by lower courts, such as District Courts. There are 13 appellate courts, each covering a specific geographic area or jurisdiction. These courts do not conduct trials; instead, they focus on whether the law was applied correctly in previous cases. Judges in the U.S. Courts of Appeals examine written briefs and hear oral arguments from both sides before making a decision. Their rulings can affirm, reverse, or modify lower court decisions, and their interpretations of the law can set important legal precedents for future cases.