What are the two main types of courts in the american judicial system

In the federal court system of the United States, the two main types of courts are district courts and circuit courts.  The district court is where any trial would start in a case that involves federal laws.  The circuit courts are the first level of appeal, if someone appeals the decision reached in district court.

There is actually a third level -- but only one court at the third level.  The Supreme Court of the United States exists as the final place for appealing a case, after decisions at the circuit court level.