Oceania is a geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern and Western hemispheres, Oceania is estimated to have a land area of 8,525,989 square kilometres and a population of over 41 million. Australia and New Zealand are two of the largest countries on the continent, with populations of 24.7 million and 4.7 million, respectively. However, the island nation of Papua New Guinea is actually more populous than New Zealand, with 8.4 million inhabitants.