Final answer:
The first national capital of the United States was in New York City, where George Washington was inaugurated. The capital moved to Philadelphia temporarily, then to the permanent site along the Potomac River, becoming the District of Columbia.
Step-by-step explanation:
The first national capital of the United States was located in New York City. On April 23, 1789, George Washington arrived in New York City to begin his presidency and took his oath of office at Federal Hall. The capital eventually moved to Philadelphia for ten years before settling at the permanent site along the Potomac River, which was selected due to the Compromise of 1790 after much debate and negotiation influenced by Alexander Hamilton, James Madison, and Thomas Jefferson. This site, chosen for the new "federal city," became known as the District of Columbia, carved out of Maryland and Virginia. Washington D.C., as we know it today, was chosen partially due to its geographic location, as it was more southern as preferred by Madison and Jefferson, but also because it was outside the jurisdiction of any individual state per Section 8 Clause 17 of the Constitution.