How many US Courts of Appeals exist?

The correct number of U.S. Courts of Appeals is 13, which includes 12 regional circuits and one Court of Appeals for the Federal Circuit. Each regional circuit serves a specific geographical area of the United States, and the Federal Circuit primarily hears specialized cases such as patent laws and certain claims against the federal government.

While the given choice of 12 is close in the context of regional circuits, one must account for the additional Federal Circuit to fully understand the structure of the appellate court system in the U.S. This system is crucial as it relays the importance of federal jurisdiction and creates a structured means for reviewing cases decided in lower courts.