Saipan is the second largest island in the Mariana Islands archipelago, after Guam. It is located about 120 mi (190 km) north of Guam and 5 nautical miles (9.3 km) northeast of Tinian, from which it is separated by the Saipan Channel. Saipan is about 12 mi (19 km) long and 5.6 mi (9.0 km) wide, with a land area of 115.38 square kilometres (44.55 sq mi).

The western side of the island is lined with sandy beaches and an offshore coral reef which creates a large lagoon. The eastern shore is composed primarily of rugged rocky cliffs and a reef.

The highest elevation on Saipan is a limestone-covered mountain called Mount Tapochau at 1,560 ft (480 m). Unlike many of the mountains in the Mariana Islands, it is not an extinct volcano, but is a limestone formation.^[2] To the north of Mount Tapochau towards Banzai Cliff is a ridge of hills. Mount Achugao, situated about 2 miles north, has been interpreted to be a remnant of a stratified composite volcanic cone whose Eocene center was not far north of the present peak.^[3]

Flora and fauna[edit]

Saipan’s flora is predominantly limestone forest. Some developed areas on the island are covered with Leucaena leucocephala, also known as “tangan-tangan” trees that were introduced some time after World War II. Remaining native forest occurs in small isolated fragments on steep slopes at low elevations and highland conservation areas of the island. Coconuts, papayas, and Thai hot peppers – locally called “Donne Sali” or “Boonie Peppers” – are among the fruits that grow wild. Mango, taro root, and bananas are a few of the many foods cultivated by local families and farmers.

Saipan is home to a number of endemic bird species. Among them: The Mariana fruit dove, White-throated Ground Dove, Bridled White-eye, Golden White-eye, and the endangeredNightingale Reed Warbler.^{[citation needed]}

The island used to have a large population of giant African land snails, introduced either deliberately as a food source, or accidentally by shipping, which became an agricultural pest. In the last few decades, its numbers have been substantially controlled by an introduced flatworm, Platydemus manokwari. Unfortunately, possibly due to the flatworm, the native tree-snails also became extinct.