There all 12 regional federal courts of appeals (the 1st through 11th Circuits, plus the D.C.Circuit). There is also a 13th federal court of appeals, called the "Court of Appeals for the Federal Circuit," whose jurisdiction is based not on geography, but subject matter.
The Federal Circuit hears all patent appeals, regardless of the region in which they were tried (so, for example, a patent case originating in Los Angeles will be tried in the federal district court for the central district of California, but will be appealed to the Federal Circuit, not the 9th Circuit). The Federal Circuit also hears all appeals from certain specialized tribunals, such as the Court of Federal Claims. It heard this case because it was an appeal from the Merit System Protection Board (the tribunal used to fire civil service workers).
Thank you for your explanation.
Coupled with what others explained, it’s beginning to make sense.