There are 13 appellate courts that sit below the U.S. Supreme Court, and they are called the U.S. Courts of Appeals. The 94 federal judicial districts are organized into 12 regional circuits, each of which has a court of appeals.
So, that accounts for 12 out of the 13. These are known as the "Circuit Courts of Appeal," e.g., "the 9th Circuit."
In addition, the Court of Appeals for the Federal Circuit has nationwide jurisdiction to hear appeals in specialized cases, such as those involving patent laws, and cases decided by the U.S. Court of International Trade and the U.S. Court of Federal Claims.
This case is a direct appeal, without having gone through ANY Article III court. No federal district court was involved at all.
How did plaintiff manage to get a direct appeal? The opinion tells us ...
We generally have jurisdiction over appeals of a final decision of the MSPB under 28 U.S.C. 1295(a)(9), pursuant to 5 U.S.C. 7703(b)(1).
Thanks for the additional information.