Final answer:
Thomas Jefferson was inaugurated as the third President of the United States in Washington, D.C., which was the nation's capital following the capital's relocation from New York City.
Step-by-step explanation:
Thomas Jefferson was inaugurated as the third President of the United States in the nation's capital city at the time, which was Washington, D.C.
This event occurred after he was elected as a leader of the Democratic-Republican Party in 1801. Notably, during his presidency, Jefferson was responsible for major achievements such as the Louisiana Purchase in 1803 and sending out the Lewis and Clark Expedition in 1804, which broadened the country's scientific and geographical knowledge.
Prior to Jefferson's inauguration, the capital had been moved from New York City to Washington, D.C. as part of a compromise orchestrated by Alexander Hamilton, often regarded as the Compromise of 1790.