The types of cases heard by federal courts are divided into two types. First, any cases involving "diversity of citizenship" in which the parties are from different states within the United States is heard by a federal court. Also, a case where two parties are from different countries would be heard by a federal court. A third type of case would be one that has been decided by a lower court but is being appealed. A fourth type of case would be one involving the US government, constitutional questions, or federal laws. These cases can be criminal, civil, or bankruptcies.
Another way of dividing up federal cases into types is as follows:
Federal questions, including federal crimes, military issues, and intellectual property.
Diversity: Cases from people resident in different states or when two states are suing each other.
Treaties and Diplomats: Cases involving US relationships with foreign countries
Admiralty: Cases that are related to waterways, including oceans, lakes, and rivers.