As you may (or may not) remember from your high school civics class, Article III of the Constitution invests the judicial power of the United States in the federal court system. Article III, Section 1 specifically creates the U.S. Supreme Court and gives Congress the authority to create the lower federal courts. Congress has used this power to establish 13 U.S. Courts of Appeals, and 94 U.S. District Courts.
As seen in the flowchart below, the course of a case is decided by which laws (federal, state, local, etc.) are involved. Since we’re currently watching the progress of the Clean Water Rule, I’ve highlighted the course involving federal laws. This diagram also explains how past wetland regulation decisions ended up in the Supreme Court. Keep in mind, the Supreme Court can decide if they will review a lower court decision or not; and certainly not all appeals to the Supreme Court are reviewed. If two lower courts disagree in their decisions, it is more likely the Supreme Court may step in for a final decision.
You can see the dashed grey boundary lines within the state, if there is more than one U.S. District Court within a state. Also, to point out the last two U.S. Court of Appeals, I circled them in orange and numbered them. The colors of the states (or U.S. territories) show the area of jurisdiction for each numbered U.S. Circuit Court of Appeals. For example, if a court case was originally filed in Michigan (Eastern District or Western District) and an appeal of a court decision is made, it will be reviewed by the 6th U.S. Circuit Court of Appeals. The exception to this occurs if there is no clear and exclusive path established for judicial review.
Now we've a more complete picture of the courts involved in the legal wranglings of the Clean Water Rule.
SUPREME COURT: Big wins elusive for EPA in Clean Water Act showdowns, by Jeremy P Jacobs, E&E reporter, Greenwire: Wednesday, August 27, 2014