LADRONE, or MARIANNE ISLANDS (so called respectively from the thievish habits of the natives, and in honour of Queen Mary Anne of Spain), a group in the N. Pacific Ocean, between Lat. 13. and 21., Long. 144 and 146. They are about twenty in number, of volcanic origin, irregular and picturesque in outline, and clothed with luxuriant vegetation. The intervening straits abound in shoals and currents, and there are few good harbours. The heat of the climate is somewhat tempered by the trade-winds. Among the vegetable products are sugar, rice, Indian corn, tobacco, cotton, indigo, &c. Of wild animals, the most numerous are swine, sometimes of large size; cattle, horses, asses, mules, and llamas, have been introduced by the Spaniards. The principal island is Guajtan, or St John, the most southerly of the group. It is about 80 miles in circumference, and has a good fortified harbour, some miles to the S. of St Ygnacio de Agaña, the seat of government. The aboriginal inhabitants, an active and athletic race, have gradually given place to a mixed population, descended of colonists from Mexico and the Philippine Isles. This group was discovered in 1521 by Magellan; but no settlement was made in them for about 150 years, when the widow of Philip IV. sent out a body of missionaries to convert the natives. They were visited in 1742 by Anson, who spent some time on the island of Tinian, where he discovered architectural remains, indicating a considerable progress in the arts of civilization.
There are two other small island groups of this name, the one on the coast of China, at the mouth of the bay of Canton, a great stronghold of pirates, the other off the coast of Guatemala.