The Republic of the Marshall Islands (RMI) consists of over 2,000 small, low-lying coral islands and islets clustered in 29 atolls and 5 single islands on a table reef (Figure C12.1). These atolls and islands form two groups: the Ratak Chain and the Ralik Chain (meaning ‘sunrise’ and ‘sunset’) and lie just north of the equator and west of the international dateline. Land area totals only 182 Km2 or 70 mi2, and protected, shallower, and resources-rich atoll lagoons comprise 10,470 Km2 or 4,040 mi2. The population density in the Marshall Islands is 296 per Km2 (766 people per mi2). About 75% of the population is urban (40,224 people in 2019) (Worldometers, 2019).