Washington state constitution
Article IV
Section 6

Superior courts and district courts have concurrent jurisdiction in cases in equity. The superior court shall have original jurisdiction in all cases at law which involve the title or possession of real property, or the legality of any tax, impost, assessment, toll, or municipal fine, and in all other cases in which the demand or the value of the property in controversy amounts to three thousand dollars or as otherwise determined by law, or a lesser sum in excess of the jurisdiction granted to justices of the peace and other inferior courts, and in all criminal cases amounting to felony, and in all cases of misdemeanor not otherwise provided for by law; of actions of forcible entry and detainer; of proceedings in insolvency; of actions to prevent or abate a nuisance; of all matters of probate, of divorce, and for annulment of marriage; and for such special cases and proceedings as are not otherwise provided for. The superior court shall also have original jurisdiction in all cases and of all proceedings in which jurisdiction shall not have been by law vested exclusively in some other court; and said court shall have the power of naturalization and to issue papers therefore. They shall have such appellate jurisdiction in cases arising in justices' and other inferior courts in their respective counties as may be prescribed by law. They shall always be open, except on nonjudicial days, and their process shall extend to all parts of the state. Said courts and their judges shall have power to issue writs of mandamus, quo warranto, review, certiorari, prohibition, and writs of habeas corpus, on petition by or on behalf of any person in actual custody in their respective counties. Injunctions and writs of prohibition and of habeas corpus may be issued and served on legal holidays and nonjudicial days.