Saipan is the largest island and capital of the Northern Mariana Islands, a Territory of the United States in the western Pacific Ocean. Accordin…Saipan is the largest island and capital of the Northern Mariana Islands, a Territory of the United States in the western Pacific Ocean. According to 2020 estimates by the United States Census Bureau, the population of Saipan was 43,385. Its people have been United States citizens since the 1980s. Saipan is one of the main homes of the Chamorro, the Indigenous people of the Mariana Islands.