Oahu one of the principal of the Hawaiian or Sandwich Islands group, is situated in 158° W. long. and between 21° and 22° N. lat., with a population in 1872 of 20,671, of whom 3129 were foreigners. It is twenty-five miles W.N.W. of Molokai, the most romantic and fertile of the whole group, and its port is the best in the islands. Honolulu, on the south side of Oahu, is the residence of the king and seat of government. Oahu is about forty-eight miles long and twenty-three miles wide. It is of volcanic formation and mountainous, but the highest peaks are clothed with vegetation. There are two distinct ranges of mountains, the windward and the leeward, called respectively the Konahuinui and the Waianae ranges. They exhibit few craters in perfect condition, but there are groups of tufa cones along the shore. The American Board have seven stations on this island. SEE SANDWICH ISLANDS.