The Supreme Court of the Commonwealth of the Northern Mariana Islands is the highest court of the United States Commonwealth of the Northern Mariana Islands (CNMI), exercising civil and criminal appellate jurisdiction over commonwealth law matters. It should not be confused with the United States District Court for the Northern Mariana Islands, which exercises jurisdiction over federal law. The Supreme Court sits in the capital, Saipan, and consists of a Chief Justice and two Associate Justices. The CNMI has no intermediate appellate commonwealth law court, which means that the CNMI Supreme Court hears appeals directly from the trial-level Superior Court.
The Supreme Court was created by commonwealth law on May 1, 1989. This was allowed under the terms of the Covenant to Establish a Commonwealth of the Northern Mariana Islands in Political Union with the United States of America of 1975 (Covenant). The Covenant granted self-government to the CNMI, with the U.S. administering the islands under the former United NationsTrust Territory of the Pacific Islands system. Prior to the creation of the Supreme Court, the Covenant provided that the U.S. District Court would exercise original jurisdiction over federal law matters and appellate jurisdiction over commonwealth law matters. With the creation of the Supreme Court, the District Court's appellate jurisdiction was effectively eliminated. However, the Covenant provided that for 15 years following the creation of a commonwealth appellate court, appeals of that court's decisions would go to the United States Court of Appeals for the Ninth Circuit, just as if the decision was rendered by the District Court. As of May 1, 2004, CNMI Supreme Court appeals can be taken directly to the United States Supreme Court, thus giving the CNMI court relative parity with the highest courts of the 50 U.S. states.