A series of courts at the federal level hear appeals of certain types of cases and decisions. A federal appellate court can hear appeals regarding decisions made by various federal agencies. They will also hear appeals of decisions made by federal courts at the district level. The courts are known as the federal circuit courts or the U.S. Courts of Appeals.
The country is divided into 13 overall circuits. Each circuit has a federal appeals court and multiple district courts under that court. Above the federal courts is the Supreme Court. According to CivilRights.org, the Supreme Court doesn't even hear 100 cases annually, but the courts directly under the highest court adjudicate tens of thousands of matters annually.