The United States of America (commonly referred to as the USA)is a federal constitutional republic comprising fifty states and a federal district. The country is situated mostly in central North America, where its forty-eight contiguous states and Washington, D.C. the capital district, lie between the Pacific and Atlantic Oceans, bordered by Canada to the north and Mexico to the south.

The climate varies along with the geography, from tropical (hot and wet in summer, warm and dry in winter) in Florida to tundra (cold all year) in Alaska. Large parts of the country have warm summers and cold winters. Some parts of the United States, like parts of California, have a Mediterranean climate.