Austronesian people settled the Northern Mariana Islands around 1500 B.C. These people became the indigenous Chamorro and were influenced by later migrations, including Micronesians in the first century A.D. and island Southeast Asians around 900. Spanish explorer Ferdinand MAGELLAN sailed through the Mariana Islands in 1521, and Spain claimed them in 1565. Spain formally colonized the Mariana Islands in 1668 and administered the archipelago from Guam. Spain’s brutal repression of the Chamorro, along with new diseases and intermittent warfare, reduced the indigenous population by about 90% in the 1700s. With a similar dynamic occurring on Guam, Spain forced the Chamorro from the Northern Mariana Islands to resettle there. By the time they returned, many other Micronesians, including Chuukese and Yapese, had already settled on their islands.

In 1898, Spain ceded Guam to the US after the Spanish-American War but sold the Northern Mariana Islands to Germany under the German-Spanish Treaty of 1899. Germany administered the territory from German New Guinea but took a hands-off approach to day-to-day life. Following World War I, Japan administered the islands under a League of Nations mandate. Japan focused on sugar production and brought in thousands of Japanese laborers, who quickly outnumbered the Chamorro on the islands. During World War II, Japan invaded Guam from the Northern Mariana Islands and used Marianan Chamorro as translators with Guamanian Chamorro, creating friction between the two Chamorro communities that continues to this day. The US captured the Northern Mariana Islands in 1944 after the Battle of Saipan and later administered them as part of the Trust Territory of the Pacific Islands (TTPI).

On four occasions in the 1950s and 1960s, voters opted for integration with Guam, which Guam rejected in 1969. In 1978, the Northern Mariana Islands was granted self-governance separate from the rest of the TTPI, and in 1986, islanders were granted US citizenship, with the territory coming under US sovereignty as the Commonwealth of the Northern Mariana Islands (CNMI). In 2009, the CNMI became the final US territory to elect a nonvoting delegate to the US Congress.