Missouri Botanical Garden
Photo by: Hong Song
- The United States of America, also referred to as the United States, U.S.A., U.S., America,¹ or the States, is a federal republic in central North America, stretching from the Atlantic in the east to the Pacific Ocean in the west. It shares land borders with Canada in the north and Mexico in the south, shares a marine border with Russia, in the west, and has a collection of districts, territories, and possessions around the world. The country has fifty states, which have a level of local autonomy according to the system of federalism. A United States citizen is usually identified as an American.
- As the world's third largest country (total area), the United States landscape varies greatly: temperate forestland on the East coast, mangrove forests in Florida, the Great Plains in the center of the country, the Mississippi-Missouri river system, the Rocky Mountains west of the plains, deserts and temperate coastal zones west of the Rocky Mountains and temperate rainforests in the Pacific Northwest. The arctic regions of Alaska and the volcanic islands of Hawaii only increase the geographic and climatic diversity.
- The climate varies along with the landscape, from sub-tropical in Florida to tundra in Alaska. Large parts of the country have a continental climate, with warm summers and cold winters. Some parts of the United States, particularly parts of California, have a Mediterranean climate.