The United States Federal Government is a name used for the chief governing body of the United States of America. It is responsible for the whole of the United States, and its power is not limited geographically in the manner which the State governments are. The Federal Government is the common government of the States, and governs those who reside within the Fifty States.
The beginnings of the United States Federal Government can be traced to the First Continental Congress, which was held during September and October of 1774. However the United States wasn't established until the Colonies separated from England, which was effectuated by the Declaration of Independence on July 4, 1776. The Congress then took upon the duties of governing the unification of the States in the ensuing American Revolution. In 1881 the colonies ratified the establishment of an official government. The Articles of Confederation, as it was called, was flawed and didn't last long. It led to the Constitutional Convention by which the States revised the Government to its current form. The Constitution and Bill of Rights were written as a result of the convention, and used as the format for the new government.
The Federal Government, was then and is now, divided into three sections: The Executive Branch, the Judiciary Branch, and the Legislative Branch. Their respective powers were and are listed in the United States Constitution. Thus the powers of the Federal Government, are the same as those listed belonging to the respective branches.