DOUGLAS GINSBURG, Federal Judge, U.S. Court of Appeals, D.C. Circuit:
The judicial branch of the United States government has two parts: the lower federal courts and the Supreme Court. Let’s take a look at the map.

The country is divided into 94 judicial districts – each with a district, or trial, court. If a U.S. district court rules against you, you can appeal to a circuit court. There are twelve circuit courts of appeals; a thirteenth court in Washington, D.C., the Federal Circuit, hears particular types of appeals, especially in patent and tax cases.
Here’s where the names get tricky. The nation’s capital has two of the circuit courts – the special court I just mentioned, and the court that I sit on – the U.S. Court of Appeals for the District of Columbia Circuit.
Washington, D.C. has its own federal court of appeals because the nations capital generates so many cases – involving, not only statutes passed by the Congress but also regulations written by federal agencies. If a U.S. Court of Appeals rules against you, you can try to appeal your case to the Supreme Court – the highest court in the land. But the odds of the Supreme Court taking your case are low. The Court receives more than 8,000 petitions a year – and accepts about 80, or one percent.
Federal courts deal mostly with the interpretation of federal law – and whether a law is constitutional. A decision by an appellate court sets a precedent for all the district courts in its circuit. The Supreme Court’s decisions, of course, bind all courts – state and federal – throughout the country.
All together the judiciary, the lower federal courts and the Supreme Court, form the vital third branch of the government.