The United States Department of State (DOS), often referred to as the State Department, is the United States federal executive department that advises the President and leads the country in foreign policy issues. Equivalent to the foreign ministry of other countries, the State Department is responsible for the international relations of the United States, negotiates treaties and agreements with foreign entities, and represents the United States at the United Nations. The Department was created in 1789 and was the first executive department established. 

The Department is headquartered in the Harry S Truman Building located at 2201 C Street, NW, a few blocks away from the White House in the Foggy Bottom neighborhood of Washington, D.C. The Department operates the diplomatic missions of the United States abroad and is responsible for implementing the foreign policy of the United States and U.S. diplomacy efforts. The Department is also the depository for more than 200 multilateral treaties. 

The Department is led by the Secretary of State, who is nominated by the President and confirmed by the Senate and is a member of the Cabinet. The current Secretary of State is Rex Tillerson, beginning 1 February 2017. The Secretary of State is the first Cabinet official in the order of precedence and in the presidential line of succession, after the President pro tempore of the Senate.
Who nominates this position?
The Department is led by the Secretary of State, who is nominated by the President