USA Time Zones: Standard Time + Daylight Saving Time + Time Zone information. The United States of America, also referred to as the United States, the U.S., the USA, America, and the States (colloquially), is a federal republic of 50 states, located primarily in central North America.
The United States has land borders with Canada and Mexico and territorial water boundaries with Canada, Russia and the Bahamas. The USA is otherwise bounded by the Pacific Ocean, the Bering Sea, the Arctic Ocean, the Atlantic Ocean, the Gulf of Mexico and the Caribbean Sea. Forty-eight of the states, "the continental" or "contiguous 48 states" are located in a single region between Canada and Mexico. The other two are Alaska and the archipelago of Hawaii.
Time zone. A time zone is a region that has a uniform standard time for legal, commercial, and social purposes.
It is convenient for areas in close commercial or other communication to keep the same time, so time zones tend to follow the boundaries of countries and their subdivisions. Most of the time zones on land are offset from Coordinated Universal Time (UTC) by a whole number of hours (UTC−12 to UTC+14), but a few are offset by 30 or 45 minutes (for example Nepal Standard Time is UTC +05:45). Some higher latitude countries use daylight saving time for part of the year, typically by changing clocks by an hour. Many land time zones are skewed toward the west of the corresponding nautical time zones.