Northern Mariana Islands, Commonwealth of the, is a chain of 16 islands in the Pacific Ocean. The islands are a commonwealth of the United States. They lie about 1,000 miles (1,600 kilometers) south of Japan and about 1,500 miles (2,400 kilometers) east of the Philippines. The Northern Marianas extend about 337 miles (543 kilometers) from north to south and cover about 179 square miles (464 square kilometers) of land. They are part of a larger region in the Pacific Ocean called Micronesia. Together with Guam, the Northern Marianas make up the Mariana Islands.