There was a period in the history of the United States, that almost all the history books fails to chronicle - the political history before Untied States elected George Washington as president ( ironically he almost ended up as king ).
There were 8 men who carried the title "President Of The United States" before George Washington was ever elected.
This era started with the adoption of The Articles of Confederation in March 1, 1781
1: John Hanson - 1781 to 1782
2: Elias Boudinot - 1782 to 1783
3: Thomas Mifflin - 1783 to 1784
4: Richard Henry Lee - 1784 to 1785
5: John Hancock - 1785 to 1786
6: Nathaniel Gorham - 1786 to 1787
7: Arthur St. Clair - 1787 to 1788
8: Cyrus Griffin - 1788 to 1789
But wait - there is more ! The Articles of Confederation is considered the first constitution of the United States, however there were men before this time that carried the title of "President of the Continental Congress" that had some authority and acted at times as mediator at congressional meetings.
This era started with the adoption of the congressional Articles of Association
1: Peyton Randolph - 1774
2: Henry Middleton - 1774 to 1775
3: Peyton Randolph - 1775 ( second term )
4: John Hancock - 1775 to 1777 ( Declaration Of Independence - 1776 )
5: Henry Laurens - 1777 to 1778
6: John Jay - 1778 to 1779
7: Samuel Huntington - 1779 to 1781
8: Thomas McKean - 1781
1: The American Revolutionary War ended in 1783, making Thomas Mifflin the first president of an independent United States
2: The United States Constitution was ratified in 1787, making Arthur St. Clair the first president under the new constitution and making Cyrus Griffin the only president ever elected by congress ( under the new constitution ).