Largest marine protected area (IUCN definition)

Based on the IUCN’s assessment criteria for protected areas, the largest marine protected area (MPA), as of September 2018, is Papahānaumokuākea Marine National Monument around the north-western end of the Hawai’ian archipelago, USA. Originally inaugurated in June 2006 with an area of 360,000 square kilometres (140,000 square miles), on 26 August 2016, the-then US President Barack Obama announced an expansion that more than quadrupled the size of the reserve; it now covers a total area of 1,508,870 square kilometres (582,578 square miles). The reserve prevents any commercial fishing or mining activities and helps to protect more than 7,000 species.

To be officially recognized and endorsed as a "marine protected area”, an MPA must meet a number of strict standards agreed by the global community and laid out by the IUCN’s World Commission on Protected Areas (WCPA) – including but not limited to:

- Conservation focused with nature as the priority

- Defined goals and objectives which reflect these conservation values

- Suitable size, location and design that will enable conservation of values

- Defined and readily understood boundary

- Management plan or equivalent, which address the needs for the conservation of the site’s major values and achievement of its social and economic goals and objectives

- Resources and capacity to implement

It must be noted that other marine areas have been designated that occupy a larger area than Papahānaumokuākea, including the Ross Sea Region Marine Protected Area (2.09 million square kilometres) in Antarctica and Marae Moana (1.99 million square kilometres) in the Cook Islands. However, based on current compliance with the principles and guidelines of the WCPA – and variable levels of conservation management and permitted usage within these reserves – the IUCN asserts that Papahānaumokuākea Marine National Monument is the most qualified to the title of largest MPA as of Sep 2018.