Some of the most important U.S. Presidents include Abraham Lincoln, Franklin Delano Roosevelt, George Washington, Thomas Jefferson and Andrew Jackson. Other important presidents include Theodore Roosevelt, Woodrow Wilson, Harry S. Truman, James K. Polk and Dwight Eisenhower.
Abraham Lincoln helped unite the states after the American Civil War, and his leadership led to the abolition of slavery. Lincoln issued the Emancipation Proclamation in 1862, which freed slaves in the Southern states. He was the 16th president of the United States, and is considered one of the most influential in the history of the nation.
Franklin Delano Roosevelt provided leadership during World War II that helped the Allies win the war. FDR won four terms as president, and created many new programs as part of the New Deal to help lead the United States out of the Great Depression. He also created the Social Security system and the Securities and Exchange Commission, both of which still operate today.
George Washington was the first president of the United States, and he set the precedent that other presidents would follow for centuries. Washington served two terms, setting a precedent that was only ever broken by one other president: Franklin Delano Roosevelt. One reason for George Washington's historical significance is his assistance of the Continental Army in defeating the British.