Marianneor Mariana Islands Ladrone, a group of about 20 islands belonging to Spain, in the north Pacific ocean, N. of the Caroline islands, between lat. 13° and 21° N., and lon. 144° and 146° E.; area, 416 sq. m.; pop. about 10,000. When the Spanish missionaries sent by Queen Mariana, widow of Philip IV. of Spain, established themselves on the islands toward the end of the 17th century, the natives numbered 40,000. The present inhabitants are mostly descendants of settlers from Mexico and the Philippines. The islands are of volcanic formation, mountainous, well watered, and well wooded. The breadfruit, banana, and cocoanut grow to perfection, and the soil is productive in sugar, rice, corn, tobacco, cotton, and indigo. The climate is salubrious, the heat being tempered by the trade winds. Horses, cattle, and llamas were early introduced by the Spaniards; wild hogs are numerous and very large. The principal islands are Guahan, Rota, Aguijan, Saypan or Seypan, and Tinian. Lord Anson visited Tinian in 1742, and found there cyclopean ruins. The seat of government is at San Ignacio de Agana, on the island of Guahan, the most southerly of the group, where there is also a good fortified harbor. Asuncion and Pagon, in the north, are noted for their volcanoes.

The general navigation is rendered dangerous by shoals and currents. A pearl fishery exists on the coast of Saypan. Magellan discovered the islands shortly before his death in 1521, and named them the Ladrones from the thievish disposition of the natives. They were afterward called the Lazarus islands, and in 1667, when the Jesuits settled there, they were renamed Marianne or Mariana in honor of the Spanish queen. - There are two other small groups called La-drones: one in China, situated at the mouth of the bay of Canton, which is a resort of pirates; the other in the Pacific, 10 m. off the coast of Colombia.