Which three cities have been locations of the U.S. capital?
Answer: New York City, Philadelphia, and Washington D.C.
Immediately after the constitution established Congress, the capital of the newly formed country was located in Philadelphia. Congress met here from March 1781 to June 1783 at which point a group of disgruntled soldiers gathered outside Independence Hall demanding repayment for their service to the country during the Revolutionary War. Although Congress called upon John Dickinson, the Governor or Pennsylvania, to help protect them from the protesters, Dickinson actually sided with the angry men and refused to assist in their removal. This lack of support lead Congress to flee briefly to Princeton New Jersey, and then ultimately New York City.
New York City was always meant to be a temporary location until a more permanent one could be agreed upon. The city served as the capital until August 12, 1790, at which point it was decided that the new capital would be built along the Potomac River. The Residence Act was passed to pave the way for the permanent relocation.
With that said, however, the capital was moved back to Philadelphia, where it remained for 10 years while the building on the Potomac River was being completed. Finally, on November 17th, 1800, the U.S. capital was moved to Washington D.C. which is where it has remained to this day.