Who was the first President of the United States?

The first President of the United States was George Washington. He served from April 30, 1789, to March 4, 1797, and is often referred to as the "Father of His Country" for his pivotal role in the founding of the nation. Washington's leadership established many protocols and traditions for the presidency, including the precedent of a two-term limit, which later became law. His election was vital in uniting the country after the American Revolution and fostering a sense of national identity.

The other figures listed—Thomas Jefferson, Abraham Lincoln, and Theodore Roosevelt—each served as presidents but at different times in U.S. history, and none was the first to hold the office. Jefferson was the third president, Lincoln was the sixteenth, and Roosevelt was the twenty-sixth, all of whom made significant contributions to the nation but not as its inaugural leader. Thus, George Washington stands distinctively as the first president, making the selected answer the only correct choice.