Kiritimati, or Christmas Island, is a Pacific Ocean raised coral atoll in the northern Line Islands. It is part of the Republic of Kiribati. The island has the greatest land area of any coral atoll in the world, about 388 square kilometres (150 square miles); its lagoon is roughly the same size. The atoll is about 150 km (93 mi) in perimeter, while the lagoon shoreline extends for over 48 km (30 mi). Kiritimati comprises over 70% of the total land area of Kiribati, a country encompassing 33 Pacific atolls and islands.