The Americas are the lands of the Western hemisphere or New World consisting of the continents of North America and South America with their associated islands and regions. The Americas cover 8.3% of the Earth's total surface area (28.4% of its land area) and contain about 14% of the human population (about 900 million people). The Americas may alternatively be referred to as America; however, America may be ambiguous as it can refer to either this entire landmass or just the United States of America.