Each state’s constitution and laws establish the state’s courts, which interpret state laws (and generally not federal laws). A court of last resort, often known as a supreme court, is usually the highest court in the state. Some states also have an intermediate court of appeals. Below these intermediate courts of appeal are the state trial courts, where most lawsuits begin. State trial courts are referred to differently in different states—often as district courts, circuit courts, or superior courts.

State courts are often courts of general jurisdiction—meaning they hear all types of cases—involving criminal law, family law, probate law, and general disputes involving money and property. But more populated counties often have courts of specific jurisdiction, such as family courts that only hear family law matters (divorce, child custody, child support); criminal courts that only hear criminal matters; and probate courts that only handle the probate of estates and related litigation.

In Washington State, the court system is structured with the Washington State Supreme Court serving as the court of last resort. Below the Supreme Court is the Washington Court of Appeals, which acts as an intermediate appellate court. At the base of the hierarchy are the Superior Courts, which function as the state trial courts of general jurisdiction. These courts handle a wide range of cases, including criminal, civil, family, and probate matters. In addition to Superior Courts, Washington also has Courts of Limited Jurisdiction, which include District Courts and Municipal Courts. These lower courts typically handle less serious criminal offenses, small claims, and traffic infractions. Larger counties may have specialized courts, such as family courts for family law matters and drug courts for certain drug offenses. The state's court system is designed to ensure that there is a clear path for appeals and that specialized matters can be addressed in appropriate settings.